JP2000251738A - Image display device, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid vacuum discharge caused by static charge by detecting an anode current from high voltage impressed on an anode electrode, stopping impression of a high voltage source when electrostatic eliminating drive is required, and driving only an element driving voltage to restrain increase of potential on an electron substrate. SOLUTION: A controller circuit 3 receives a control signal and a data bus from a computer 2, and performs an aging process. A high voltage is impressed from a high voltage power supply 8 to a high voltage terminal on the face plate side. A current value of row-direction wiring is detected by a current detecting circuit 5 and is fed as If data into the controller circuit 3, next, in an anode current detecting circuit 7, during aging, an anode current flowing every row-direction wiring is detected, and is fed as Ie data into the controller circuit 3. A charged state is determined by detecting both of If and Ie and deriving, for example, efficiency η=Ie/If and change of only Ie.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device using a surface conduction electron-emitting device as an electron beam source and arranging a plurality of these devices in a two-dimensional plane, and a method of manufacturing the same.

[0002]

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

As a surface conduction electron-emitting device, for example, M.S. I Elinson, Radio Eng. E
electron Phys. , 10, 1290, (19
65) and other examples described later.

The surface conduction electron-emitting device utilizes a phenomenon in which electron emission occurs when a current flows in a thin film having a small area formed on a substrate in parallel with the film surface. As the surface conduction electron-emitting device, in addition to the use of a thin film of SnO ₂ according to the Ellingson, etc., by an Au thin film [G. Dittmer: "Thin SolidF
ilms ", 9,317 (1972)] and In ₂ O ₃ /
According to SnO ₂ thin film [M. Hartwell an
d C.I. G. FIG. Fonstad: "IEEETrans.
ED Conf. , 519 (1975)] and those using carbon thin films [Hisashi Araki et al .: Vacuum, Vol. 26, No. 1
No. 22 (1983)].

[0005] As a typical example of the device configuration of these surface conduction electron-emitting devices, FIG. Hartw
FIG. 2 shows a plan view of an element by ell or the like. In FIG.
001 is a substrate, and 3004 is a conductive thin film made of a metal oxide formed by sputtering. 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 distance L between the device electrodes in the figure is 0.5 to 1 m.
m and W are set at 0.1 mm. 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.
It does not faithfully represent the actual position and shape of the electron-emitting portion.

[0006] M. In the above-described surface conduction type electron-emitting device including the device by Hartwell et al., The conductive thin film 3004 is subjected to an energization process called energization forming before the electron emission, so that the electron emission portion 30 is formed.
05 was common. That is, the energization forming is to apply a constant DC voltage to both ends of the conductive thin film 3004, or to apply a DC voltage that increases at a very slow rate of, for example, about 1 V / min, and energize the conductive thin film 3004.
The electron emitting portion 30 in a state where the conductive thin film 3004 is locally destroyed, deformed or deteriorated, and is in an electrically high resistance state.
05 is formed.

[0007] A crack is generated in a part of the conductive thin film 3004 which has been 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.

An example of the FE type is disclosed in, for example, W.S. P.
Dyke & W. W. Dolan, "Field emi
session ", Advance in Electro
nPhysics, 8, 89 (1956) or C.I. A. Spindt, "Physical prop
artists of thin-film fiel
de emission cathodes with
molybdenium cones ", J. App.
l. Phys. , 47, 5248 (1976).

As a typical example of the FE type device configuration, FIG. A. 1 shows a cross-sectional view of an element according to Spindt or the like. In the figure, reference numeral 3010 denotes a substrate;
Is an emitter wiring made of a conductive material, 3012 is an emitter cone, 3013 is an insulating layer, and 3014 is a gate electrode. This device comprises an emitter cone 3012 and a gate electrode 3
By applying an appropriate voltage during 014, field emission is caused from the tip of the emitter cone 3012.

FIG. 1 shows another element structure of the FE type.
There is also an example in which an emitter and a gate electrode are arranged on a substrate almost in parallel with the plane of the substrate, instead of the laminated structure as in 2.

As an example of the MIM type, for example,
C. A. Mead, “Operat-ion of
unnel-emission Devices, J. et al.
Appl Phys. , 32, 646 (1961).

FIG. 13 shows a typical example of the MIM type element configuration.
Shown in The figure is a sectional view, in which 3020 is a substrate, 3021 is a lower electrode made of metal, 3022 is a thin insulating layer having a thickness of about 100 °, and 3023 is a thickness of 80 to 3
The upper electrode is made of a metal of about 00 °.

In the MIM type, electrons are emitted from the surface of the upper electrode 3023 by applying an appropriate voltage between the upper electrode 3023 and the lower electrode 3021.

The above-described cold cathode device can obtain electrons at a lower temperature than the hot cathode device, and thus does not require a heater for heating. Therefore, the structure is simpler than that of the hot cathode element, and a fine element can be produced. Further, even 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. Also, unlike the hot cathode element, which operates by heating the heater, the response speed is slow, and the cold cathode element has the advantage that the response speed is fast.

For this reason, research for applying the cold cathode device has been actively conducted. For example, a surface conduction electron-emitting device has the advantage that a large number of devices can be formed over a large area because it has a particularly simple structure and is easy to manufacture among cold cathode devices. Therefore, as disclosed in Japanese Patent Application Laid-Open No. 64-31332 by the present applicant, a method for arranging and driving a large number of elements has been studied.

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.

Particularly, as an application to an image display device, for example, US Pat. No. 5,066,883, Japanese Patent Application Laid-Open No. 2-257551 and Japanese Patent Application Laid-Open No. 4-28137 by the present applicant.
As disclosed in Japanese Unexamined Patent Publication, an image display device using a combination of a surface conduction electron-emitting device and a phosphor that emits light by irradiation with an electron beam has been studied.

An image display device using a combination of a surface conduction electron-emitting device and a phosphor is expected to have better characteristics than other conventional image display devices. For example, compared to a liquid crystal display device that has become widespread in recent years, it can be said that it is superior in that it does not require a backlight because it is a self-luminous type and that it has a wide viewing angle.

A method of driving a large number of FE types is disclosed in US Pat. No. 4,904,8 by the present applicant.
No. 95. Further, as an example in which the FE type is applied to an image display device, for example, R.F. A flat panel display reported by Meyer et al. Is known.

[R. Meyer: "Recent De
development on Mic-rotics D
display at LETI ", Tech. Dige
stof 4th Int. Vacuum Micr
oeletronicsConf. , Nagaham
a, 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.

Among the image forming apparatuses using the above-described electron-emitting devices, a flat display device having a small depth has been noticed as a replacement for a cathode-ray tube display device because it is space-saving and lightweight. I have.

FIG. 14 is a perspective view showing an example of a display panel portion forming a flat-panel image display device, in which a part of the panel is cut away to show the internal structure.

In the figure, 3115 is a rear plate, 3116
Denotes a side wall, 3117 denotes a face plate, and a rear plate 3115, a side wall 3116, and a face plate 3
117 forms an envelope (airtight container) for maintaining the inside of the display panel in a vacuum.

A substrate 3111 is fixed to the rear plate 3115. On this substrate 3111, n × m surface conduction electron-emitting devices 3112 are formed (n, m).
m is a positive integer of 2 or more, and is appropriately set according to the target number of display pixels. ).

The n × m surface conduction electron-emitting devices 3
Reference numeral 112 denotes m row-directional wirings 31 as shown in FIG.
13 and n column-directional wirings 3114. The substrate 3111 and the surface conduction electron-emitting device 31
12, the part constituted by the row direction wiring 3113 and the column direction wiring 3114 is called a multi-electron beam source. An insulating layer (not shown) is formed at least at a portion where the row wiring 3113 and the column wiring 3114 intersect, so that electrical insulation is maintained.

A fluorescent film 3118 made of a phosphor is formed on the lower surface of the face plate 3117, and phosphors of three primary colors of red (R), green (G) and blue (B) (not shown) are applied. Divided. A black body (not shown) is provided between the respective color phosphors forming the fluorescent film 3118, and a metal back 3119 made of Al or the like is formed on the surface of the fluorescent film 3118 on the rear plate 3115 side. I have.

Dx1 to Dxm and Dy1 to Dyn and Hv are electric connection terminals having an airtight structure provided for electrically connecting the display panel to an electric circuit (not shown).

Dx1 to Dxm are the row wirings 3113 of the multiple electron beam source, Dy1 to Dyn are the column wirings 3114 of the multi-electron beam source, and Hv is the metal back 311.
9 respectively.

The inside of the airtight container is 10 ^-6 Torr.
r, and as the display area of the image display device increases, means for preventing deformation or destruction of the rear plate 3115 and the face plate 3117 due to a pressure difference between the inside and the outside of the airtight container is required. . Rear plate 3115 and face plate 311
The method of thickening 6 not only increases the weight of the image display device, but also causes image distortion and parallax when viewed from an oblique direction.

On the other hand, in FIG. 14, a structural support (referred to as a spacer or a rib, not shown in FIG. 14) made of a relatively thin glass plate for suppressing the atmospheric pressure is provided. In this way, the distance between the substrate 3111 on which the multi-beam electron source is formed and the face plate 3116 on which the fluorescent film 3118 is formed is usually kept at a sub-millimeter to several millimeters, and the inside of the airtight container is kept at a high vacuum as described above. ing.

In the image display apparatus using the display panel described above, when a voltage is applied to each surface conduction electron-emitting device 3112 through the external terminals Dx1 to Dxm and Dy1 to Dyn, each surface conduction electron-emitting device 3112 is applied.
The electrons are emitted from. At the same time metal back 31
By applying a high voltage of several hundred V to several kV through the external terminal Hv to 19, the emitted electrons are accelerated and collide with the inner surface of the face plate 3117.

As a result, the phosphor of each color constituting the fluorescent film 3118 is excited and emits light to display an image.

[0033]

However, in such an image display device, a vacuum discharge or a change in element characteristics may occur due to a voltage charged on the substrate 3111 during operation.

Such a phenomenon is explained with reference to FIGS. First, FIG. 15 shows the number of vacuum discharges when the element was driven experimentally using the image display device of FIG.
It was shown to. The figure shows an increase in vacuum discharge with an increase in the high voltage Hv. It is apparent that the frequency of the vacuum discharge depends on the high voltage Hv. In addition, there is a high possibility that some elements on the matrix are damaged by the discharge.

The vacuum discharge may be caused by various factors, one of which may be the voltage caused by charging the matrix substrate as described above. The reason will be described with reference to FIGS.

FIG. 16 (a) schematically shows the driving state of FIG. 14 and the state of charging the matrix wiring when paying attention to the face plate 3116, the substrate 3111 and the line adjacent to the driving line L. It is. A drive voltage Vdr is applied to the drive lines L on the matrix,
A high voltage Hv is applied to the face plate side.

The face plate 3116 and the substrate 3
There is an inter-substrate capacitance Chv between the substrates 111 and a substrate capacitance Csub between the substrates 3111. Further, a surface resistance Rsurf on the substrate exists between the matrix wirings. FIG.
In (b), the equivalent circuit based on the surface resistance and between the upper and lower substrates in the image display device is represented using the R and C parameters described above. According to FIG. 16B, the charging mechanism on the matrix wiring is based on the inter-substrate capacitance Chv and the substrate capacitance Csub.
It has been experimentally confirmed that the charging is caused by both the capacity division and the electron emission when the element is driven.
In other words, it is considered that the charge generated by exciting the phosphor on the face plate 3116 by the electrons emitted by driving the element is charged on the matrix substrate 3111 as ions having a positive potential and raises the potential. Can be Further, the potential value changes depending on the value of the high voltage Hv.

The above description is supported by FIG. FIG. 17 shows the image display device of FIG.
The time change of the surface potential Vsurf when V is applied and the current value Iprobe of the line L and the line adjacent to the line L when only one line of the element is driven are measured. It can be seen that, during the period in which the high voltage Hv is applied and the element is not driven, the surface potential Vsurf decreases toward the voltage determined by the capacitance division of each capacitance Chv and Csub.

Next, when the driving voltage Vdrv is applied to the driving line L to drive the element, it is detected that the current value Iprobe flowing into the adjacent line through the surface resistance Rsurf is increased by the driving of the element. As a result, Vsurf becomes approximately Vsur from the voltage value before driving during the above-described element driving time, including ΔV = about 8 V.
f = 15V was observed.

From the above measurement results, the potential charged on the adjacent line rises in the positive direction when the element is driven, so that the positive charge generated from the phosphor surface causes the potential on the substrate surface to rise as described above. It is thought that it is. It has been confirmed that Vsurf also depends on the value of the high voltage Hv. For example, it has been confirmed that when Hv = 5.0 kV, the potential increases to ΔV = 15.0 V.

As described above, the charging of ionized charges in a vacuum creates a state where discharge is likely to occur when a high voltage is applied to drive the element to generate an emission current and excite the phosphor. . It is faceplate 3116 and substrate 3
It also depends on the residual gas between 111 and the vacuum state. Also,
It has also been confirmed that when the high voltage Hv is increased to increase the occurrence of ionization in order to increase the probability of occurrence of discharge, the number of discharges increases as shown in FIG. Furthermore, it has been experimentally confirmed that the emission current Ie is increased by the charged potential. The following can be considered as this phenomenon.

The charging causes a change in the state of the electric field on the matrix substrate. Particularly, in the vicinity of the element, the element driving voltage Vf
As a result, a change in the electric field was caused, the number of electrons reaching the anode side increased, and a change in the beam shape excited by the phosphor was confirmed. As a result, it was confirmed from the above phenomenon that the anode current was increased by charging.

Rsurf is determined by the sheet resistance value of the substrate 3111. For example, Rsurf has a value of 1 × 10E15Ω / □ for a quartz substrate. Further, when the surface potential Vsurf is increased by applying the high voltage Hv and actually driving the element (for example, line-sequential driving), the emission current Ie increases or the element current Ie increases.
It can be confirmed by the change in efficiency Ie / If obtained from f. Therefore, the potential state can be predicted by detecting the efficiency or the emission current while driving the element.

The above-mentioned phenomenon can be said to be the same in the aging process for producing the image display device.

The aging step will be described with reference to FIG. FIG. 18 is a view schematically showing the steps of the manufacturing process of the image display device shown in FIG. 14, and the present invention is not limited to this process. FIG. 14 shows a structure using a surface conduction electron-emitting device. As described with reference to FIG. 11, a step of forming a surface conduction electron-emitting device formed on a matrix substrate 3111 as an electron source generator at an intersection of a matrix. Then, a step of forming a phosphor on a face plate 3116 as a light emitting display panel is performed, and both substrates are bonded to each other by a sealing assembly process. Then, vacuum evacuation is performed, and if necessary, baking is performed as a degassing step, and further, sealing and getter flash are performed.

In the image display device manufactured by the above-described steps, there are cases where the brightness is reduced and a point defect or a line defect occurs in the display at the initial stage of the operation. One of these causes is a phosphor on the face plate 3116, a metal back, etc., wirings, electrodes, and the like disposed in the matrix substrate 3111.
The desorption of gas molecules from the electron-emitting portion or the like occurs, thereby deteriorating the vacuum state and reducing the function as an image display device. The aging step is one of the steps performed to reduce the amount of outgassing from members in each display device as a measure against such deterioration of the vacuum state.

In the degassing step, there is a method of reducing degassing by performing a high-temperature vacuum baking process.
Considering the heat resistance and the like of the members and the like, there is a limit in the baking temperature, and the above problem has not been essentially solved. Therefore, in the aging step, the image display device is driven by applying a high voltage, and the driving load is gradually increased with the elapse of time to degas the inside of the display device.

The load at the time of aging here means a driving voltage for driving the element, a high voltage, a driving frequency,
Driving duty and driving time.

As described above, in the aging step, as described above, charging of the surface potential on the matrix substrate during driving of the element similarly occurs. Therefore, it has been found that in the present problem, the yield is reduced due to the destruction of the element due to the occurrence of the vacuum discharge during the production of the display device, which is a problem.

In view of the above problems, it is an object of the present invention to provide a method of manufacturing a highly reliable image display device which removes a voltage charged on a matrix substrate of the image display device and avoids a vacuum discharge caused by the charging. A display device is provided.

[0051]

In order to achieve the above object, an image display apparatus according to the present invention comprises m × n surface conduction electron-emitting devices connected to a simple matrix structure by row and column wiring. In a manufacturing process and an image display device of an image display device having an element substrate and a phosphor plate in which a phosphor and an anode electrode opposed to each electron-emitting device are arranged in a position facing the element substrate in a plane, the anode electrode It has a detecting means for detecting the anode current from the high voltage to be applied, and determines whether or not to perform the static elimination drive by the detecting means, and when the static elimination drive is required, stops the application of the high-voltage power supply, This is to drive only the element drive voltage and suppress an increase in the potential on the element substrate.

According to the structure of the present invention, there is a problem in a process of manufacturing an image display device using a surface conduction electron-emitting device and in a case of displaying as an image display device.

1) In response to a problem caused by vacuum discharge caused by an increase in the potential charged on the substrate surface, the emission current or efficiency is detected, and it is determined from the change in the value that the substrate surface potential is increasing. The value of the voltage Hv is set to 0 V, and only the element driving is performed. As a result, the scattering of electrons emitted from the vicinity of the driving element serves to neutralize the positive charges charged on the substrate surface, and the so-called neutralization function acts to substantially suppress the rise in potential. Becomes possible.

The above operation is achieved by the Vsurf shown in FIG.
Can easily be inferred from the potential change of FIG. 1 shows a potential change of a part of the matrix wiring, and the surface potential Vs
The rf rises from Vb to a potential of Vs by charging the substrate surface by driving the element and applying the high voltage Hv for a time T1, and then stopping the high voltage Hv (only element driving) and Hv and the element for a time T2. It is the figure which compared the static elimination action at the time of driving stop.

From FIG. 1, when the static elimination is started at the time T2, the potential V2 in the case where only the element driving is performed is shorter than the reduction time of the potential V1 due to stopping both the element driving and Hv. It can be said that the reduction time is shorter than the time required for static elimination. In other words, static elimination when both element driving and Hv are stopped requires a long static elimination time because the charged potential decreases with a time constant depending on the resistance value of the substrate surface. Therefore, although it is possible to perform static elimination by any of the above methods, it is preferable to stop Hv and perform only the element driving in order to positively eliminate static and suppress a rise in the potential of the substrate surface. high.

By applying the above-described means, it is possible to eliminate the cause of the occurrence of vacuum discharge and to protect the elements on the matrix substrate.

2) It is also possible to solve the problem of reducing the yield in the manufacturing process of the image display device during the aging process. That is, as described above, the reduction of the vacuum discharge can be achieved by performing the charge removing operation, and it is possible to suppress the occurrence of point defects and line defects due to element destruction during the process.

[0058]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.

Referring to FIG. 1, a method for removing the charged potential in the aging step which is one of the manufacturing steps of the image display device of the present invention will be described in detail.

The description of the aging step has been described above and will not be repeated. It is assumed that the image display unit 1 has already completed the process of FIG. Next, in a state of being connected to a driving driver for performing aging, the column-directional wiring D
The column direction wiring side driver 4 is connected to y1 to Dyn, and the row direction wiring side driver 6 is connected through the current detection circuit 5 in the row wiring directions Dx1 to Dxm.

Further, the column direction wiring side driver 4 and the row direction wiring side driver 6 are connected to the column direction power supply 10 and the row direction power supply 9 respectively, and the electrode of the row wiring and the column wiring has the Vf voltage of 1 Vf.
+ 1 / 2Vf is applied to the column-direction wiring side and -1 / 2Vf is applied to the row-direction wiring side so that a voltage of / 2 is applied. Next, a plurality of control signals are input from the controller circuit 3 to the row and column direction wiring side drivers 4 and 6 and driven based on those signals.

The controller circuit 3 receives a control signal and a data bus from the computer 2 for controlling a drive sequence for performing aging, and an aging process is performed based on these signals.

Next, a high voltage is applied from the high voltage power supply 8 to the high voltage terminal on the face plate side through the anode current detection circuit 7. At this time, a signal detecting the anode current (Ie data) is input to the controller circuit 3. Further, in order to control the output of the anode voltage Va of the high voltage power supply 8, a high voltage control signal for Va control is output from the controller circuit 3 to the high voltage power supply.

Next, a driving method based on the aging step will be described. Aging is to gradually increase the driving load while applying Va to the element, so that the computer 2 controlling the driving sequence issues
The set values of the drive frequency, the drive pulse width, the drive time, the drive voltage, the high voltage, and the data in the column direction wiring on the controller circuit 3 are output to the data bus, and the aging drive is performed by the control signal. Control the system.

The signals input from the controller circuit 3 to the computer 2 include the current value (I
f data), the anode current value (Ie data), and the like.
In the control circuit 3, first, the row direction wiring side driver 6
A horizontal synchronizing signal for line-sequentially driving the row direction wiring of the image display unit 1 and a corresponding driving frequency setting signal for each driving frequency are output. Since the drive frequency setting signal starts from a state where the horizontal drive frequency is low at the beginning of aging, the pulse width of the drive voltage applied to the row direction wiring is output as a signal corresponding to the horizontal drive frequency.

For example, if the driving frequency is f = 15 hz and the number of row wirings is 480, T = 1/1
5hz x 1/480 pulse width signal (approx.
The set value corresponding to c) is output.

Next, a vertical synchronizing signal, a horizontal synchronizing signal, and column direction wiring data are output from the control circuit 3 to the column direction wiring side driver 4. The column wiring data is a voltage of a wiring resistance generated from a row wiring current value per one which flows when the selected row wiring is driven, with respect to + ／ Vf applied to the column wiring. A correction voltage for compensating for the drop is output. The correction voltage is set in synchronization with the horizontal and vertical synchronization signals.
Thereby, a desired voltage is correctly applied to each element in the image display unit.

The row direction wiring current value is determined by the current detection circuit 5
Is detected by In the current detection circuit 5, for example, a shunt resistor is connected in series for each row wiring, and the value can be known by providing a circuit for detecting a voltage across the shunt resistor. The detected value is converted into an analog or digital value as voltage data and input to the controller circuit 3 as If data. In the controller circuit 3, the voltage drop is calculated based on the wiring resistance value of each row wiring stored in advance as data with respect to the detected current value.

Each row wiring resistance data is stored in the computer 2
May be stored in the internal memory. Next, the anode current detection circuit 7 detects an anode current flowing for each row wiring when line-sequentially driven during aging. As a method for detecting the anode current, a detection circuit configuration similar to the above-described current detection circuit 5 for the row wiring may be used. The detection circuit is converted into an analog or digital value as voltage data and is input to the controller circuit 3 as an anode current (Ie data). .

With the above detection method, the controller circuit 3 detects a change in Ie while performing aging drive, calculates a change in Ie with respect to the aging drive time, and controls the high-voltage power supply 8 according to the value. Do.

Next, a specific driving in the present invention will be described.
This will be described with reference to FIGS. FIG. 3 shows temporal changes in If and Ie when the drive frequency, the drive pulse width, the drive time when Va is applied, and the drive voltage Vf are fixed and the aging load is increased by increasing the Va in the aging drive. It is a graph expressed as. If here
Denotes the sum of the current values of the respective elements formed on the row-direction wiring by the aging drive, which corresponds to If data detected by the row-direction wiring current value, and Ie denotes the emission current emitted from the respective elements. This is the same as the Ie data detected by the anode current detection circuit obtained in synchronization with each row-direction wiring drive. Also,
FIG. 4 is a diagram showing a drive sequence for explaining FIG. 3, and in the first embodiment, FIG. 3 will be described based on the sequence of FIG.

First, the initial setting of S1 is performed by the computer 2
In the present embodiment, the driving conditions are set as follows from the method of increasing Va. Drive frequency f = 3.7
5hz, pulse width Pw = 28 μsec, drive voltage Vf =
15V, high voltage step VaUP = 1.0 kV, high voltage start voltage and end voltage S / E = 1 kV / 3 k
V, the high voltage application time Ta = 30 min, the neutralization action time (Va = 0 V) Tb = 15 min, the change rate ΔIe from the initial value Ie and η = + 10%, and Δη = + 50%.

In the first embodiment, the action of removing the potential charged on the surface of the substrate is realized by stopping the high voltage and driving the element. As a method of detecting the charging status, both If and Ie are detected and the efficiency η (η = Ie / I
Although both f) and the rate of change of Ie alone are determined, only one of Ie and η may be determined.

The values of the driving conditions and the like in the initial setting are set values on the assumption that the driving load is started from the lightest condition when aging is started, and are limited to the setting values of the present conditions. Not something. In addition, the aging step is not completed only with the set value, but after the drive condition set in the initial setting is completed, aging with the changed condition is performed again.

Next, the aging drive in S2 will be described. Element driving is started based on the conditions set in S1. The driving conditions are set from the computer 2 through the controller circuit 3 to the row-direction wiring driver 6 and the column-direction wiring driver 4, and a voltage Vf is applied to the elements in the image display unit 1. Further, the high voltage is set for the high voltage power supply 8 and the aging drive is started. that time,
A correction voltage in consideration of the wiring resistance of the row wiring is also superimposed on the column wiring driver 4. In this embodiment, Vf = 1
Va = 1.0 kV is applied as 5V.

Next, the If / Ie measurement in S3 and the calculation of η will be described. When the aging drive starts, If, If and A are detected by the current detection circuit 5 and the anode current detection circuit 7.
If is detected, and the efficiency η is calculated based on the value. FIG. 3 shows, as a representative value, changes in If and Ie during aging for an arbitrary row-direction wiring having the image display 1. At the start of aging drive, If
1 and Ie1 are obtained and the efficiency η1 (Ie1 / If
1) is calculated. The measurement is performed at a sampling interval set by the sequence program while the aging drive sequence is being executed. The measurement and the calculation of the efficiency are performed in all the aging-driven row-direction wirings, and the obtained data is sequentially stored in a memory in the computer 2.

Next, the determination of the allowable values of Ie and η in S4 will be described. In S4, I measured for each row-direction wiring
e and η are the initial values Ie set in the initial value setting S1.
And the change rate with respect to η is set as an allowable value, and a comparison is made with respect to the allowable value. Specifically, for example, the change rates of If and Ie at Va = 1 kV in FIG.
Based on Ie and η obtained by measuring e and If, ΔIe =
By calculating Ie−Ie1 / Ie and Δη = η−η1 / η, the change rates ΔIe and Δη are obtained.

The initial values are the values of Ie and η measured at the start of aging drive and the set drive time Ta in the sequence, and the aging drive is performed by increasing the aging load Va next. First Ie, η measured at
Is targeted. In addition, the neutralization time Tb for performing the static elimination ends, and I is measured first after the Va is newly applied.
e and η are also targets of the initial values.

Next, the determination of the end of the driving time in S5 will be described. In S5, it is determined whether or not the predetermined driving time Ta has been completed for the set Va load. If the driving time has ended, the sequence proceeds to a sequence for performing VaUP as the next step. If the driving time has elapsed, the process returns to S3 and aging at the set Va is continued.

Next, the VaUP judgment in S6 will be described. In S6, it is determined whether or not to increase Va after the aging load ends the set driving time Ta.

From the start voltage and the end voltage of Va set in the initial value setting, it is determined whether or not the aging drive is to be ended. When the drive time Ta ends when Va = 3 kv, one of the aging processes ends. Conversely, when Va is not applied up to 3 kv, VaUP is continuously performed in S7.

Next, VaUP in S7 will be described.
In S7, the high voltage Va for resetting the aging load is reset. Va is set at a set time Ta.
Is completed, the next Va is supplied to the high voltage power supply 8 by the high voltage control signal from the computer 2 and the control circuit 3.
The value is set. In the present embodiment, since the step of the high voltage Va is 1 kv, for example, after aging of T1 is completed, Va = 2 kv is set in S6.

Next, a description will be given of Va = 0V (static elimination drive) in S8 determined from the allowable value determination from S4. As described above, in order to determine whether or not the rate of change of Ie, η exceeds the allowable value in S4, FIG.
Is used, the rate of change of Ie and η when Va = 2 kV is used. V
When a = 2 kV, the initial values Ie2 and η2 after the application of Va are measured. As the aging sequence goes on,
Ie2 ′, η ′ measured at the time T2 is the rate of change ΔIe = + 10 of the set allowable value from the initial values Ie2, η2.
%, Δη = + 50% or more. It has been experimentally confirmed that the value of Ie is originally fixed by fixing the Va and Vf values in the aging step, and that If is gradually reduced or almost constant.

Therefore, I at Va = 2 kv in FIG.
Regarding the changes in f and Ie, although the value of If slightly decreases from If2 to If3, the value increases from Ie2 to Ie2 ′, thereby increasing η. Therefore, as described above, the decrease is considered to be an increase in potential due to charges charged on the matrix substrate, and it is determined that it is necessary to perform static elimination driving. As described above, in S8, assuming that Va = 0 V, the device driving with only Vf is performed for the set time Tb.
Done during ΔIe and Δη indicate the relative amounts of change of If and Ie, and are not limited to the numbers of wirings in the row and column directions of the image display device 1.

Next, the resetting of Va in S9 will be described. After the neutralization drive is completed, Va is set again. V
The value of a is reset to the value of Va at the time when it is determined that the drive for static elimination is performed. Then, the process returns to S3 in order to perform aging for the time Tc in FIG.

After the aging of the time Tc is completed,
As the next step, aging at Va = 3.0 kv is performed for Ta time. By the above steps, Va
The aging sequence when is raised is completed.

In the first embodiment, the static elimination drive
This applies to all row-directional wiring. Row direction wiring D
If any one of x1 to Dxm exceeds the set change rate, the static elimination drive is performed. Also,
Vf is fixed at the time of driving for static elimination, but there is also a method of increasing Vf at the time of aging driving to promote the static elimination effect. The Vf value in that case is desirably set at a voltage lower than the max Vf value applied to the element in the manufacturing process up to aging.

As described above, in the aging step in the manufacturing process of the image display section 1, by performing the aging drive in the above steps, it is possible to suppress the potential rise due to the electric charges charged on the substrate surface and to avoid the vacuum discharge. It became. This makes it possible to prevent the occurrence of point defects and line defects during the process, and it is possible to expect an effect of protecting the element.

Next, a second embodiment of the present invention will be described. FIG. 5 is a schematic diagram illustrating an image display device according to the second embodiment. In this embodiment, a method for performing static elimination driving when the image display apparatus is actually driven will be described.

First, as an explanation of the image display device, the image display unit 1 is the same as that of the first embodiment. As a driving method, the scanning method is line-sequential, and in order to give a gradation to a display image, the emission period of the phosphor is controlled by controlling the electron emission period within one horizontal scanning time (1H) by the time width of the modulation signal. It is based on controlling the total amount and expressing gradation.

In FIG. 5, the signal separation circuit 12 is an NTS
From video signals such as C, horizontal sync signal, vertical sync signal,
This is a circuit for producing digital video signals and the like. These include a video intermediate frequency circuit, a video detection circuit, a synchronization separation circuit, a low-pass filter, an A / D conversion circuit, a timing control circuit, and the like.

Reference numeral 14 denotes a scanning signal side driver for driving the row direction wiring of the image display unit.
Is a circuit for outputting a scanning signal based on the horizontal synchronizing signal separately manufactured in the above.

Reference numeral 13 denotes a modulation signal side driver for driving the wiring in the column direction of the image display unit.
This is a circuit that outputs a modulation signal from a horizontal synchronization signal, a vertical synchronization signal, a digital video signal, and the like, which are separately manufactured in the above.

A circuit 16 detects the power state of the image display apparatus, and outputs a signal corresponding to ON / OFF of the power switch.

Further, reference numeral 15 denotes a controller for controlling the display device based on the SW OFF signal.
This is the timer circuit that outputs to the timer. When the signal from the timer circuit 15 is in the active state, a signal corresponding to Va = 0 V is output. Reference numerals 7 and 8 denote a high-voltage power supply 8 and an anode current detection circuit 7 as in the first embodiment.

FIG. 10 shows a row-direction wiring (that is, a wiring for supplying a scanning signal) and a column-direction wiring (that is, a side for supplying a modulation signal) when driving the image display unit of the image display device of the present invention. 2 shows an example of a timing chart of a voltage applied to a lead line of the wiring of FIG.

The timing chart of FIG. 13 shows the voltage applied to the row direction wirings of the I, I + 1, and I + 2 rows when the rows I, I + 1, and I + 2 of the image display device are sequentially driven, and the modulation. Column direction wirings J, J + 1, J + on the signal side
FIG. 9 is a diagram illustrating voltages applied to two columns of column direction wiring. (1 <I <M−2, 1 <JN−2, where M is the number of wirings in the row direction and N is the number of wirings in the column direction). In the figure, in one horizontal scanning period K, display of the I-th row, K + 1
Indicates the (I + 1) th row, and K + 2 indicates the (I + 2) th row.

The row direction wirings on the scanning side in line-sequential scanning are sequentially selected every one horizontal scanning period (hereinafter referred to as 1H), and the row direction wirings of the selected row correspond to 1H. Scan signals having a pulse height of -1/2 Vf (Vf is a drive voltage in this case, approximately Vf = 2 Vth) are sequentially applied. After the scanning is performed on the omnidirectional wiring, the scanning is repeated from the first row again.

The column wiring has a peak value of 1/2 Vf corresponding to the video signal displayed on the selected row in synchronization with the scanning signal applied to the row wiring. The modulation signal is applied to all the column wirings.

The modulation signal rises in synchronization with the rise of the operation signal, and has a peak value of 1 for a time corresponding to the video signal.
The voltage rises after maintaining the state of / 2 Vf (hereinafter, the period from the rise of the modulation signal to the next rise is simply referred to as the pulse width of the modulation signal).

The pulse width of the modulation signal corresponds to the luminance of the video signal displayed on the selected row when the video signal is separated into three colors of RGB. However, in actuality, it is necessary to display a high-quality image. It is not a simple proportional relationship because it applies various corrections to. As described above, by applying the voltage, the drive voltage Vf is applied to the surface conduction emission type elements in the selected row by the pulse width of the modulation signal. Since the emission current Ie of the surface conduction emission type element has the above-mentioned clear threshold characteristic with respect to Vf, an image corresponding to a desired video signal is displayed on the selected row as a result. Further, by performing operations in a line-sequential manner, an image is displayed over all the surface conduction electron-emitting devices in the image display unit.

Next, the static elimination action of the second embodiment will be described. As a method of performing the static elimination drive in the image display device, for example, detecting the rate of change of Ie and stopping Va for a certain time during image display as in the first embodiment can be performed by the image display device. Impossible. For this purpose, a switch ON / OFF detection circuit 16 for detecting a change in the power supply state is provided to detect that the switch of the image display device has been turned OFF, and output a signal to the timer circuit 15.
The timer circuit 15 recognizes that the SW signal is OFF, and outputs a Va = 0V instruction signal for performing the static elimination driving to the control circuit 11 for a predetermined time. And the control circuit 11
Based on the signal of the timer circuit 15, the Va control of the high voltage power supply 8 is set to 0V by the high voltage control signal.

FIG. 6 shows a timing chart corresponding to the above control. First, when the SW is turned off at the time T1 of the image display device, the SW is turned on / off.
An OFF logic level signal is output from the F detection circuit. The timer circuit 15 activates the timer counter by catching a change in the signal at the time of OFF, for example, a fall of the signal from H to L in the present embodiment.

The timer counter outputs a logic signal (L → H level in this embodiment) determined by the counter circuit set in the timer circuit and corresponding to Va = 0 to the controller circuit 11 for a time period Ta. I do. The controller circuit 11 detects a change in the signal of the timer circuit 13 and starts the charge elimination drive.

The static elimination drive is performed during Ta, and the high-voltage control signal Va = 0 is set from the control circuit 11 to the high-voltage power supply 8. On the other hand, the scanning driver 14 and the modulation signal The driver 13 is driven as it is. Then, the timer counter determines that Ta
When the period of time has expired, the output signal of the timer counter is changed from H to L, and the controller circuit 11 releases the static elimination drive by catching the change of the signal and stops the element driving.

In the above control, the anode current detection circuit 7
Although the static elimination drive is performed without detecting the anode current Ie from the device, the static elimination drive may be performed by taking in the value of the anode current value Ie. Specifically, for example, when a timer counter signal for a time Ta is output, the controller circuit 11 detects the value of the anode current Ie and determines whether or not to perform the static elimination drive on the detected value. Is also good.

As a determination method, comparison with Ie is performed by using a comparator circuit or the like, and if Ie is equal to or more than the set Ie value set in the comparator circuit, static elimination driving is performed. Then, if Ie becomes equal to or less than the set value within the Ta time, the neutralization drive is completed at that time.

If the value of Ie is equal to or greater than the set value even after the elapse of the time Ta, the static elimination drive is continued. In this case, the anode current Ie is converted as an electrical signal (an analog signal or a digital signal through an AD converter) and input to the comparator circuit. Furthermore,
The set Ie value set by the comparator circuit is changed according to the value of Va applied when the display is driven by the image display device.

Further, as another method, the time of Ta may be set according to the state time of SW. In that case, the timer circuit 13 sets the SW ON / OFF detection circuit 16
The ON time is measured based on the signal from. If the ON time of the image display device is short, the time of Ta is shortened, and if the ON time is long, Ta is lengthened. Also at this time, the anode current Ie may be detected and control using the above-described comparator circuit may be performed. Thus, it is possible to perform the charge elimination drive according to the image display drive time.

As another method, a CPU or a sequencer may be provided in the controller, and the static elimination drive may be performed by a sequence process. FIG. 7 shows a flowchart in the case of performing the operation in a sequence, and will be briefly described. At S10, the ON / OFF state of the SW is determined. If the SW is in the OFF state, the value of the anode current Ie is detected in S11 to determine whether or not the drive for static elimination is necessary. Next, when performing static elimination driving, the timer is set in S12. The static elimination time corresponds to the Ta time described above.

Next, in step S13, a charge elimination drive is performed. In the static elimination drive, the static elimination is performed for the time set in S12 with Va = 0V and the element drive ON. When it is determined that the charge elimination drive has been completed in S14, the value of Ie is detected again in S15, and it is determined whether or not the charge elimination drive is stopped. Then, in the case of stopping the static elimination driving, the element driving is turned off in S16.

As described above, in the second embodiment, the ON /
Detecting the OFF signal enables the control of the static elimination drive. According to this embodiment, static elimination drive can be performed in accordance with the display time of the image display device, the static elimination effect is improved, and the reliability of the display device is improved by preventing surface potential increase, which is one of the causes of vacuum discharge. .

Further, even when the ON / OFF of the SW is repeated within a short time (for example, when switching from a TV to a game), the static elimination drive can be performed by the method of the second embodiment.

Next, a third embodiment of the present invention will be described. In the present embodiment, the charge removal drive is performed even during image display. Since the configuration of the image display circuit, the control circuit for image display, and the like are all the same as in the second embodiment, the description is omitted.

As a control method of the third embodiment,
When the value of Ie detected by the anode current detection circuit 7 exceeds the set value Ie, a time Ta for performing the charge removal drive is set by the timer circuit. From the start of the set Ta signal, a high-voltage control signal of Va = 0 is output once every several frames in synchronization with the horizontal synchronizing signal to perform static elimination. FIG. 8 shows a timing chart thereof, which will be specifically described.

First, the anode current Ie is always taken into the controller circuit 11 from the anode current detection circuit 7. In the controller circuit 11, a comparator circuit is used as in the second embodiment. If the detected Ie is equal to or greater than the set value Ie, the comparator circuit outputs a timer circuit through the controller circuit 11. The signal is input to 15.

The timer circuit 15 outputs a timer signal Ta by detecting the input signal. The method of outputting Ta is the same as in the second embodiment. When the timer signal Ta is output, the controller circuit 11 detects a change (L → H) of the signal and outputs a signal of Va = 0 while synchronizing with the horizontal synchronizing signal.

When the horizontal synchronizing signal is an NTSC signal, the synchronizing signal is output at a cycle of 60 Hz.
For example, in the third embodiment, a counter for counting the horizontal synchronizing signal and a synchronizing circuit for synchronizing the Ta signal and the horizontal synchronizing signal make one counter for two fields (one frame).
The counter is set so that a signal of Va = 0 V is output to the high-voltage power supply 8 at a rate of the number of times. Thereby, control to the high voltage power supply 8 is about 16 m.
Va = 0 V during the second, and the period of the charge elimination driving in which only the element driving is performed exists once in one frame.

By performing the above-described control, it is possible to realize the drive for removing electricity from the display device even during image display. The setting of the charge elimination drive can be made by changing the set value of the counter that counts the horizontal synchronization signal. When flickering or the like affects the display of an image due to the static elimination drive cycle set in the present embodiment, the counter setting value may be increased to lengthen the static elimination drive cycle. In that case, it is better to increase the set time of Ta.

Further, also in the third embodiment, the value of Ie is detected, and if the value of Ie becomes equal to or less than the set value Ie within the set time Ta, the charge elimination drive may be canceled. If the value of Ie is equal to or greater than the set value of Ie even after the end of the Ta period, the drive for static elimination is continued.

Further, as another method similar to the second embodiment, a CPU or a sequencer may be provided in the controller, and the static elimination drive may be performed by a sequence process. FIG. 9 shows a flowchart in a case where the sequence processing is performed, and the flow will be briefly described.

First, in step S17, the anode current Ie is determined. If the anode current Ie is equal to or greater than the set Ie value, in step S18, a timer setting Ta for static elimination driving is performed. Next, in step S19, a predetermined horizontal synchronization signal is counted from the horizontal synchronization signal based on a preset count value, and then in step S20, static elimination driving is performed with Va = 0 only for element driving. The static elimination drive control is the same as the control described above.

Next, it is determined at S21 whether the set time Ta has expired. If the set time has expired, the anode current Ie is detected again in S22. If the set time is less than the set value, Va is set at a predetermined voltage in S23, the horizontal synchronization counter is disabled, and normal image display driving is performed. Do. If the value of Ie is equal to or higher than the set value and the charge elimination drive is necessary, the charge elimination drive is continued until the value becomes equal to or less than the set value.

As described above, in the third embodiment, it is possible to perform the static elimination drive even during the image display, and to suppress the surface potential rise which is one of the factors of the vacuum discharge as in the second embodiment. The reliability of the display device has also been improved.

[0125]

As described above, according to the present invention,
Process of manufacturing an image display device using surface conduction electron-emitting devices, and vacuum discharge due to an increase in potential charged on the substrate surface, which was a problem when displaying as an image display device, and images during the manufacturing process It is possible to solve the problem of reducing the yield in the manufacturing process of the display device.

That is, by performing the charge eliminating operation, a reduction in vacuum discharge can be achieved, and the occurrence of point defects and line defects due to device destruction during the manufacturing process can be suppressed. This has made it possible to establish a highly reliable process.

Also, by using the method of the present invention for an image display device, the life of the element can be extended, and a stable image display can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a change in surface potential for explaining the present invention.

FIG. 2 is a schematic diagram showing an aging drive device according to the first embodiment.

FIG. 3 is a diagram illustrating If during aging according to the first embodiment.
It is a figure which shows / Ie change.

FIG. 4 is a diagram illustrating a process of a charge elimination drive during aging according to the first embodiment.

FIG. 5 is a schematic diagram illustrating a drive circuit of an image display device according to a second embodiment.

FIG. 6 is a diagram showing a timing chart when performing static elimination drive in the second embodiment.

FIG. 7 is a diagram showing a process when performing a charge elimination drive according to the second embodiment.

FIG. 8 is a diagram illustrating a timing chart when performing static elimination driving in the third embodiment.

FIG. 9 is a diagram illustrating a process when performing a charge elimination drive according to the third embodiment. Flowchart diagram

FIG. 10 is a diagram showing a drive timing chart in the first embodiment.

FIG. 11 is a schematic diagram showing one configuration example of a conventional surface conduction electron-emitting device.

FIG. 12 is a schematic view showing one configuration example of a conventional FE element.

FIG. 13 is a schematic view showing a configuration example of a conventional MIM element.

FIG. 14 is a schematic diagram illustrating an example of a configuration of a conventional flat panel image display device.

FIG. 15 is a diagram showing the number of discharges with respect to a high voltage in the flat panel display.

16A and 16B are a schematic diagram illustrating a surface potential state of a flat image display and a schematic diagram illustrating an equivalent circuit.

FIG. 17 is a diagram showing a surface potential at the time of display driving in the flat panel display.

FIG. 18 is a process chart showing an example of a method for manufacturing a flat panel image display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image display part 2 Computer 3 Controller circuit 4 Column direction wiring side driver 5 Current detection circuit 6 Row direction wiring side driver 7 Anode current detection circuit 8 High voltage power supply 9 Row direction power supply 10 Column direction power supply 11 Control circuit 12 Signal separation circuit 13 Modulation Signal side driver 14 Scanning signal side driver 15 Timer circuit 16 SW ON / OFF detection circuit 17 Column power supply 18 Row power supply

Claims (9)

[Claims] 1. The method of claim 1, wherein m × n surface conduction electron-emitting devices are:
Image display having an element substrate connected in a simple matrix structure by row and column wiring, a phosphor facing each electron-emitting device at a position facing the element substrate, and a phosphor plate having anode electrodes arranged in a plane. An image display apparatus, comprising: a detection method for determining a change in a surface potential on the element substrate; and a drive for removing the surface charge on the element substrate by the detection means. Manufacturing method. 2. The image according to claim 1, wherein in the charge elimination driving, application of a high voltage from a high voltage power supply applied to the anode electrode is stopped, and only the surface conduction electron-emitting device is driven. A method for manufacturing a display device. 3. The device according to claim 1, wherein the detecting means detects an anode current flowing from the high voltage to an anode electrode and a row direction current value flowing on a row direction wiring of the matrix element substrate. 3. The method for manufacturing an image display device according to 1. 4. The charge removing drive according to claim 1, wherein the anode current or both the anode current and the row direction current are performed based on a change amount of each current value from a conduction time. 3. The method for manufacturing an image display device according to item 3. 5. m × n surface conduction electron-emitting devices,
Image display having an element substrate connected in a simple matrix structure by row and column wiring, a phosphor facing each electron-emitting device at a position facing the element substrate, and a phosphor plate having anode electrodes arranged in a plane. An image display apparatus, comprising: a detection unit for determining a change in a surface potential on the element substrate; and a drive for removing a surface charge on the element substrate by the detection unit. 6. The image display according to claim 5, wherein in the neutralization driving, application of a high voltage from a high-voltage power supply applied to the anode electrode is stopped, and only the surface conduction electron-emitting device is driven. apparatus. 7. The image display device according to claim 5, wherein the detection unit detects an anode current flowing from the high voltage to an anode electrode. 8. The image forming apparatus according to claim 5, wherein the static elimination driving is performed based on a unit that detects a change in a power supply state of the image display device and a change amount of the anode current value. An image display device according to claim 1. 9. The image forming apparatus according to claim 5, wherein the charge elimination driving is performed in synchronization with a horizontal synchronization signal of the image display device.
9. The image display device according to any one of 8.