Title: Method of controlling image display
Abstract: This invention discloses an arrangement for suppressing an erroneous display and suppressing damage to an image display apparatus when a power source is turned on, the power source is turned off, an outlet is removed, or power fails. Particularly, this invention discloses an arrangement for stopping, for a predetermined time, input of a scanning signal or modulation signal to a display panel or application of an accelerating potential in turning on the power source. This invention discloses an arrangement for stopping input of a scanning signal or modulation signal to the display panel, and then stopping supply of power in turning off the power source.
Patent Number: 6,972,741 Issued on 12/06/2005 to Isono, et al.
| Inventors:
|
Isono; Aoji (Kanagawa, JP);
Yamazaki; Tatsuro (Tokyo, JP)
|
| Assignee:
|
Canon Kabushiki Kaisha (Tokyo, JP)
|
| Appl. No.:
|
719523 |
| Filed:
|
October 5, 1999 |
| PCT Filed:
|
October 5, 1999
|
| PCT NO:
|
PCT/JP99/05473
|
| 371 Date:
|
April 25, 2001
|
| 102(e) Date:
|
April 25, 2001
|
| PCT PUB.NO.:
|
WO00/21063 |
| PCT PUB. Date:
|
April 13, 2000 |
Foreign Application Priority Data
| Oct 06, 1998[JP] | 10-284492 |
| Current U.S. Class: |
345/75; 345/74.1 |
| Intern'l Class: |
G09G 003/20 |
| Field of Search: |
345/741- 752,60,101,87,74
307/64
313/309,306,336,495-497
315/169.1,136.4,1,205,169.4
427/77,78
445/212.4,6
323/274
348/140.1
|
References Cited [Referenced By]
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| 5569974 | Oct., 1996 | Morikawa et al.
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| 5578906 | Nov., 1996 | Smith.
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| 5659329 | Aug., 1997 | Yamanobe et al.
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| 5682085 | Oct., 1997 | Suzuki et al.
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| 5721560 | Feb., 1998 | Cathey, Jr. et al.
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| 1997-0031143 | Jun., 1997 | KR.
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| WO 96/1551/9 | May., 1996 | WO.
| |
Other References
R. Meyer, "Recent Development on "Microtips" Display at LETI," Technical Digest
of 4th Int. Vacuum Microelectronics Conf., Nagahama (1991), pp. 6-9.
"Electrical Conduction And Electron Emission of Discontinuous Thin Films", G.
Dittmer, Thin Film Solids, 9 (1972), pp. 317-328.
"Electroforming and Electron Emission of Carbon Thin Films", Hisashi Asaki et
al., Vacuum, vol. 26, No. 1, pp. 22-29 (1983).
"Strong Election Emission From Patterned Tin-indium Oxide Thin Films", M. Hartwell
et al., International Electron Devices Meeting, Washington DC (1975) pp. 519-521.
"The Emission of Hot Electrons and The Field Emission of Electrons From Tin Oxide",
M. I. Elinson et al., Radio Engineering and Electronic Physics, Jul. 1965, pp. 1290-1296.
"Field Emission", W.P. Dyke et al., Advances In Electronics and Electron Physics,
(1956), pp. 89-185.
"Physical Properties of Thin-Film Field Emisssion Cathodes With Molybedium Cones",
J. Appl. Phys., 47,5248 (1976), pp. 5248-5263.
"Operation of Tunnel-Emission Devices". C.A.Mead, J. Appl. Phys., vol. 32, No.
4, Apr. 1961, pp. 646-652.
|
Primary Examiner: Shalwala; Bipin
Assistant Examiner: Dharia; Prabodh
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper & Scinto
Claims
1. An image display apparatus comprising:
a display panel for displaying an image by irradiating a fluorescent substrate
with electrons from an electron source; an acceleration potential supply circuit
for supplying to said display panel an acceleration potential for accelerating
electrons from the electron source;
a scanning circuit for supplying a scanning signal to said display panel;
a modulation circuit for supplying a modulation signal to said display panel; and
a control circuit for outputting a signal for stopping output of the signal from
said scanning circuit and/or said modulation circuit to said display panel, wherein
supply of power to said scanning circuit and/or said modulation circuit is stopped
in a state in which the output of the signal from said scanning circuit and/or
said modulation circuit to said display panel is stopped by said signal for stopping
in turning off a power source while an image based on a video signal is displayed
by outputting a signal from said scanning circuit and/or said modulation circuit
to said display panel.
2. The image display apparatus according to claim 1, wherein the electron source
comprises a plurality of row-direction wiring lines for receiving a scanning signal,
a plurality of column-direction wiring lines for receiving a modulation signal,
and a plurality of electron emitting devices connected to the row-direction wiring
lines and the column-direction wiring lines.
3. An image display apparatus comprising:
a display panel for displaying an image by irradiating a fluorescent substrate
with electrons from an electron source; an acceleration potential supply circuit
for supplying to said display panel an acceleration potential for accelerating
electrons from the electron source;
a scanning circuit for supplying a scanning signal to said display panel;
a modulation circuit for supplying a modulation signal to said display panel; and
a control circuit for outputting a signal for stopping output of the signal from
said scanning circuit and/or said modulation circuit to said display panel, wherein
supply of power to said scanning circuit and/or said modulation circuit is stopped
in a state in which the output of the signal from said scanning circuit and/or
said modulation circuit to said display panel is stopped by said signal for stopping
in performing emergency shutdown while an image based on a video signal is displayed
by outputting a signal from said scanning circuit and/or said modulation circuit
to said display panel.
4. The image display apparatus according to claim 3, wherein the electron source
comprising a plurality of row-direction wiring lines for receiving a scanning signal,
a plurality of column-direction wiring lines for receiving a modulation signal,
and a plurality of electron emitting devices connected to the row-direction wiring
lines and the column-direction wiring lines.
5. An image display apparatus comprising:
a display panel for displaying an image by irradiating a fluorescent substrate
with electrons from an electron source; an acceleration potential supply circuit
for supplying to said display panel an acceleration potential for accelerating
electrons from the electron source;
a scanning circuit for supplying a scanning signal to said display panel;
a modulation circuit for supplying a modulation signal to said display panel; and
a control circuit for outputting a signal for stopping output of the signal from
said scanning circuit and/or said modulation circuit to said display panel, wherein
supply of power to said scanning circuit and/or said modulation circuit is stopped
in a state in which the output of the signal from said scanning circuit and/or
said modulation circuit to said display panel is stopped by the signal for stopping
when a voltage abnormality is observed while an image based on a video signal is
displayed by outputting a signal from said scanning circuit and/or said modulation
circuit to said display panel.
6. The image display apparatus according to claim 5, wherein the electron source
comprising a plurality of row-direction wiring lines for receiving a scanning signal,
a plurality of column-direction wiring lines for receiving a modulation signal,
and a plurality of electron emitting devices connect to the row-direction wiring
lines and the column-direction wiring lines.
7. An image display apparatus comprising:
a display panel for displaying an image by irradiating a fluorescent substrate
with electrons from an electron source; an acceleration potential supply circuit
for supplying to said display panel an acceleration potential for accelerating
electrons from the electron source;
a scanning circuit for supplying a scanning signal to said display panel;
a modulation circuit for supplying a modulation signal to said display panel;
a first power source for supplying power to said acceleration potential supply
circuit and/or said scanning circuit and/or said modulation circuit;
a second power source for supplying power to said scanning circuit and/or said
modulation circuit upon an emergency shutdown; and
a control circuit for outputting a signal for stopping output from said acceleration
potential supply circuit and/or said scanning circuit and/or said modulation circuit
to said display panel upon an emergency shutdown wherein the signal for stopping
is outputted by using power supplied at the initial stage after switching said
first power source to said second power source.
8. The image display apparatus according to claim 7, wherein the electron source
comprising a plurality of row-direction wiring lines for receiving a scanning signal,
a plurality of column-direction wiring lines for receiving a modulation signal,
and a plurality of electron emitting devices connected to the row-direction wiring
lines and the column-direction wiring lines.
9. An image display apparatus comprising:
a display panel for displaying an image by irradiating a fluorescent substrate
with electrons from an electron source; an acceleration potential supply circuit
for supplying to said display panel an acceleration potential for accelerating
electrons from the electron source;
a scanning circuit for supplying a scanning signal to said display panel;
a modulation circuit for supplying a modulation signal to said display panel;
a first power source for supplying power to said acceleration potential supply
circuit and/or said scanning circuit and/or said modulation circuit;
a second power source for supplying power to said scanning circuit and/or said
modulation circuit, wherein said second power source comprises a capacitor or a battery;
a control circuit for outputting a signal for stopping output from said acceleration
potential supply circuit and/or said scanning circuit and/or said modulation circuit
to said display panel, wherein said signal for stopping is outputted by using power
supplied at the initial stage after switching said first power source to said second
power source.
10. The image display apparatus according to claim 9, wherein the electron source-comprising
a plurality of row-direction wiring lines for receiving a scanning signal, a plurality
of column-direction wiring lines for receiving a modulation signal, and a plurality
of electron emitting devices connected to the row-direction wiring lines and the
column-direction wiring lines.
Description
The present invention relates to an image display apparatus control method and,
more particularly, to a power-on/off control method and emergency shutdown control
method for an image display apparatus using an image display panel having a multi
electron source on which a plurality of cold cathode devices are wired in a matrix,
and fluorescent substances for emitting light upon irradiation with an electron
beam from each cold cathode device.
BACKGROUND ART
Conventionally, two types of devices, namely a thermionic cathode
device and cold cathode device, are known as electron-emitting devices. Known examples
of the cold cathode devices are surface-conduction type emitting devices, field
emission type emitting devices (to be referred to as FE type emitting devices hereinafter),
and metal/insulator/metal type emitting devices (to be referred to as MIM type
emitting devices hereinafter).
As surface-conduction type emitting devices, e.g., M. I. Elinson, Radio Eng.
Electron
Phys., 10, 1290 (1965) and other examples (to be described later) are known.
The surface-conduction type emitting device utilizes the phenomenon that electrons
are emitted by flowing a current through a small-area thin film formed on a substrate
in parallel with the film surface. The surface-conduction type emitting device
includes an emitting device using an Au thin film [G. Dittmer, "Thin Solid Films",
9,317 (1972)], an emitting device using an In
2O
3/SnO
2
thin film [M. Hartwell and C. G. Fonstad, "IEEE Trans. ED Conf. ", 519 (1975)],
an emitting device using a carbon thin film [Hisashi Araki et al., "Vacuum", Vol.
26, No. 1, p. 22 (1983)], and the like, in addition to an emitting device using
an SnO
2 thin film by Elinson et al.
FIG. 28 is a plan view showing the device by M. Hartwell et al. described above
as a typical example of the device structures of these surface-conduction type
emitting devices. In FIG. 28, reference numeral 3001 denotes a substrate;
and 3004, a conductive thin film made of a metal oxide formed by sputtering.
The conductive thin film 3004 has an H-shaped flat pattern, as shown in
FIG. 28. The conductive thin film 3004 undergoes electrification processing
(to be referred to as forming processing), thereby forming an electron-emitting
portion 3005. An interval L in FIG. 28 is set to 0.5 to 1 [mm], and W is
set to 0.1 [mm]. The electron-emitting portion 3005 is illustrated in a
rectangular shape at the center of the conductive thin film 3004 for the
sake of illustrative convenience. However, this does not exactly show the actual
position and shape of the electron-emitting portion.
In the above surface-conduction type emitting devices by M. Hartwell et al. and
the like, typically the electron-emitting portion 3005 is formed by performing
electrification processing called forming processing for the conductive thin film
3004 before electron emission. In electrification forming, a constant DC
voltage or a DC voltage which rises at a very low rate of, e.g., about 1 V/min
is applied across the conductive thin film 3004 to locally destroy, deform
or denature the conductive thin film 3004, thereby forming the electron-emitting
portion 3005 with an electrically high resistance. Note that the locally
destroyed, deformed or denatured part of the conductive thin film 3004 has
a fissure. When an appropriate voltage is applied to the conductive thin film 3004
after electrification forming, electrons are emitted near the fissure.
Known examples of the FE type devices are described in W. P. Dyke and W. W.
Dolan, "Field emission", Advance in Electron Physics, 8, 89 (1956) and C. A. Spindt,
"Physical properties of thin-film field emission cathodes with molybdenium cones",
J. Appl. Phys., 47, 5248 (1976).
FIG. 29 is a sectional view showing the device by C. A. Spindt et al. described
above as a typical example of the FE type device structure. In FIG. 29, reference
numeral 3010 denotes a substrate; 3011, an emitter wiring line made
of a conductive material; 3012, an emitter cone; 3013, an insulating
layer; and 3014, a gate electrode. This device is caused to produce a field
emission from the tip of the emitter cone 3012 by applying an appropriate
voltage between the emitter cone 3012 and the gate electrode 3014.
As another FE type device structure, there is an example in which an emitter
and
gate electrode are arranged on a substrate to be almost parallel to the substrate
surface, instead of the multilayered structure of FIG. 29.
A known example of the MIM type emitting devices is described in C. A. Mead,
"Operation
of tunnel-emission Devices, J. Appl. Phys., 32,646 (1961).
FIG. 30 shows a typical example of the MIM type device structure. FIG. 30 is
a sectional view. Reference numeral 3020 denotes a substrate; 3021,
a lower metal electrode; 3022, a thin insulating layer having a thickness
of about 100 Å; and 3023, an upper metal electrode having a thickness
of about 80 to 300 Å. The MIM type emitting device emits electrons from
the surface of the upper electrode 3023 by applying an appropriate voltage
between the upper electrode 3023 and the lower electrode 3021.
Since these cold cathode devices can emit electrons at a lower temperature,
compared to the thermionic cathode devices, the cold cathode devices do not require
any heater. The cold cathode device has a structure simpler than that of the thermionic
cathode device, and it is possible to fabricate elements that are finer. Even if
many devices are arranged on a substrate at a high density, problems such as heat
fusion of the substrate hardly arise. In addition, the response speed of the cold
cathode device is high, while the response speed of the thermionic cathode device
is low because it operates upon heating by a heater.
For this reason, applications of the cold cathode devices have enthusiastically
been studied.
Of cold cathode devices, the surface-conduction type emitting device has a simple
structure and can be easily manufactured to allow forming many devices on a wide
area. As disclosed in Japanese Patent Laid-Open No. 64-31332 filed by the present
applicant, a method of arranging and driving many devices has been studied.
Regarding applications of the surface-conduction type emitting devices
to, e.g., image forming apparatuses such as image display apparatuses and image
recording apparatuses, charge beam sources, and the like have been studied.
Particularly as an application to image display apparatuses, as disclosed
in the U.S. Pat. No. 5,066,883 and Japanese Patent Laid-Open Nos. 2-257551 and
4-28137 filed by the present applicant, an image display apparatus using a combination
of surface-conduction type emitting devices and fluorescent substances which emit
light upon irradiation with an electron beam has been studied. This type of image
display apparatus using a combination of surface-conduction type emitting devices
and fluorescent substances is expected to exhibit more excellent characteristics
than other conventional image display apparatuses. For example, compared with recent
popular liquid crystal display apparatuses, the above display apparatus is superior
in that it does not require any backlight because of a self-emission type and that
it has a wide view angle.
A method of driving many FE type emitting devices arranged side by side is disclosed
in, e.g., U.S. Pat. No. 4,904,895 filed by the present applicant. As a known example
of an application of FE type emitting devices to an image display apparatus is
a flat display apparatus reported by R. Meyer et al. [R. Meyer: "Recent Development
on Microtips Display at LETI", Tech. Digest of 4th Int. Vacuum Microele-ctronics
Conf., Nagahama, pp. 6-9 (1991)].
An example of an application of many MIM type emitting devices arranged side
by
side to an image display apparatus is disclosed in Japanese Patent Laid-Open No.
3-55738 filed by the present applicant.
The present inventors have examined cold cathode devices of various materials,
manufacturing methods, and structures, in addition to the prior arts. Further,
the present inventors have made extensive studies on a multi electron beam source
having many cold cathode devices, and an image display apparatus using this multi
electron beam source.
FIG. 31 shows a multi electron beam source by an electrical wiring method examined
by the present inventors. More specifically, this multi electron beam source is
constituted by two-dimensionally arranging many cold cathode devices, and wiring
these devices in a matrix, as shown in FIG. 31. In FIG. 31, reference numeral 4001
denotes a schematic cold cathode device; 4002, a row-direction wiring line;
and 4003, a column-direction wiring line. In practice, the row-direction
wiring line 4002 and column-direction wiring line 4003 have finite
electrical resistances, which are represented as wiring resistances 4004
and 4005 in FIG. 31. This wiring method is called a simple matrix wiring method.
For the illustrative convenience, the multi electron beam source is illustrated
in a 6×6 matrix, but the size of the matrix is not limited to this. For example,
in a multi electron beam source for an image display apparatus, devices enough
to display a desired image are arranged and wired.
In a multi electron beam source in which cold cathode devices are wired in a
simple
matrix, appropriate electrical signals are applied to the row-direction wiring
line 4002 and column-direction wiring line 4003 in order to output
a desired electron beam. For example, to drive cold cathode devices on an arbitrary
row in the matrix, a selection voltage Vs is applied to the row-direction wiring
line 4002 on the row to be selected, and at the same time a non-selection
voltage Vns is applied to the row-direction wiring lines 4002 on unselected
rows. In synchronism with this, a driving voltage Ve for outputting an electron
beam is applied to the column-direction wiring lines 4003. According to
this method, so long as voltage drops across the wiring resistances 4004
and 4005 are neglected, a voltage Ve-Vs is applied to cold cathode devices
on the selected row, and a voltage Ve-Vns is applied to cold cathode devices on
the unselected rows. If the voltages Ve, Vs, and Vns are set to appropriate levels,
an electron beam having a desired intensity must be output from only cold cathode
devices on the selected row. If different driving voltages Ve are applied to respective
column-direction wiring lines, electron beams having different intensities must
be output from respective devices on the selected row. If the application time
of the driving voltage Ve is changed, the electron beam output time must be changed.
Hence, a multi electron beam source having cold cathode devices wired in a
simple matrix can be applied for variety purposes. For example, if an electrical
signal corresponding to image information is properly applied, the multi electron
beam source can be preferably used as an electron source for an image display apparatus.
In practice, however, the multi electron beam source having cold cathode devices
wired in a simple matrix suffers the following problems.
When the power source of the image display apparatus is turned on, before outputs
to be applied from voltage power sources to row-direction wiring lines and column-direction
wiring lines stabilize, the outputs from the power sources are applied to the multi
electron beam source to damage cold cathode devices.
The same phenomenon occurs when the power source is turned off.
When the potential difference between an acceleration potential for accelerating
electrons from the electron source and a potential supplied to the electron source
in order to emit electrons is large, and particularly when the potential difference
between the electron emission potential and the acceleration potential is 500 V
or more, 3 kv or more, or 5 kV or more, an unexpected power source operation may
occur while a high acceleration potential is applied. In this case, a discomfort
display state may be generated, or the performance of the display panel such as
the characteristics of the fluorescent substance may be influenced.
It is an object of an invention according to the present application to improve
the display state and reduce damage to the image display apparatus when a power
source is turned on, the power source is turned off, an outlet is removed, or power fails.
DISCLOSURE OF INVENTION
According to one invention of the present application, an image display
apparatus control method is characterized by comprising, when image display is
to be started by outputting a signal from a modulation circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, stopping the output from the modulation circuit to the
display panel until the signal output from the modulation circuit to the display
panel is determined.
According to another invention of the present application, an image display
apparatus control method is characterized by comprising, when image display is
to be started by outputting a signal from a modulation circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, delaying the output of the signal from the modulation circuit
to the display panel after a power source is turned on, and determining the signal
output from the modulation circuit to the display panel during the delay time.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a modulation circuit to a display
panel for displaying an image by irradiation with electrons from an electron source
to fluorescent substances, stopping application of an acceleration potential for
accelerating electrons from the electron source until the signal output from the
modulation circuit to the display panel is determined.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a modulation circuit to a display
panel for displaying an image by irradiation with electrons from an electron source
to fluorescent substances, delaying application of an acceleration potential for
accelerating electrons from the electron source after a power source is turned
on, and determining the signal output from the modulation circuit to the display
panel during the delay time.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a scanning circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, stopping the output from the scanning circuit to the display
panel until the signal output from the scanning circuit to the display panel is determined.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a scanning circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, delaying the output of the signal from the scanning circuit
to the display panel after a power source is turned on, and determining the signal
output from the scanning circuit to the display panel during the delay time.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a scanning circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, stopping application of an acceleration potential for accelerating
electrons from the electron source until the signal output from the scanning circuit
to the display panel is determined.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a scanning circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, delaying application of an acceleration potential for accelerating
electrons from the electron source after a power source is turned on, and determining
the signal output from the scanning circuit to the display panel during the delay time.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a modulation circuit to a display
panel for displaying an image by irradiation with electrons from an electron source
to fluorescent substances, stopping the output from the modulation circuit to the
display panel until a power source voltage of the modulation circuit reaches a
desired value.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a modulation circuit to a display
panel for displaying an image by irradiation with electrons from an electron source
to fluorescent substances, delaying the output of the signal from the modulation
circuit to the display panel after a power source is turned on, and setting a power
source voltage of the modulation circuit to a desired value during the delay time.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a modulation circuit to a display
panel for displaying an image by irradiation with electrons from an electron source
to fluorescent substances, stopping application of an acceleration potential for
accelerating electrons from the electron source until a power source voltage of
the modulation circuit reaches a desired value.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a modulation circuit to a display
panel for displaying an image by irradiation with electrons from an electron source
to fluorescent substances, delaying application of an acceleration potential for
accelerating electrons from the electron source after a power source is turned
on, and setting a power source voltage of the modulation circuit to a desired value
during the delay time.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a scanning circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, stopping the output from the scanning circuit to the display
panel until a power source voltage of the scanning circuit reaches a desired value.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a scanning circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, delaying the output of the signal from the scanning circuit
to the display panel after a power source is turned on, and setting a power source
voltage of the scanning circuit to a desired value during the delay time.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a scanning circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, stopping application of an acceleration potential for accelerating
electrons from the electron source until a power source voltage of the scanning
circuit reaches a desired value.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when image display
is to be started by outputting a signal from a scanning circuit to a display panel
for displaying an image by irradiation with electrons from an electron source to
fluorescent substances, delaying application of an acceleration potential for accelerating
electrons from the electron source after a power source is turned on, and setting
a power source voltage of the scanning circuit to a desired value during the delay time.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when a power source
is to be turned off while is displayed by outputting a signal from a modulation
circuit to a display panel for displaying an image by irradiation with electrons
from an electron source to fluorescent substances, stopping the output of the signal
from the modulation circuit to the display panel, and then stopping supply of power
to the modulation circuit.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when a power source
is to be turned off while an image is displayed by outputting a signal from a scanning
circuit to a display panel for displaying an image by irradiation with electrons
from an electron source to fluorescent substances, stopping the output of the signal
from the scanning circuit to the display panel, and then stopping supply of power
to the scanning circuit.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when emergency
shutdown is to be performed while an image is displayed by outputting a signal
from a modulation circuit to a display panel for displaying an image by irradiation
with electrons from an electron source to fluorescent substances, stopping the
output of the signal from the modulation circuit to the display panel, and then
stopping supply of power to the modulation circuit.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when emergency
shutdown is to be performed while an image is displayed by outputting a signal
from a scanning circuit to a display panel for displaying an image by irradiation
with electrons from an electron source to fluorescent substances, stopping the
output of the signal from the scanning circuit to the display panel, and then stopping
supply of power to the scanning circuit.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when a voltage
abnormality is observed while an image is displayed by outputting a signal from
a modulation circuit to a display panel for displaying an image by irradiation
with electrons from an electron source to fluorescent substances, stopping the
output of the signal from the modulation circuit to the display panel, and then
stopping supply of power to the modulation circuit.
According to still another invention of the present application, an image
display apparatus control method is characterized by comprising, when a voltage
abnormality is observed while an image is displayed by outputting a signal from
a scanning circuit to a display panel for displaying an image by irradiation with
electrons from an electron source to fluorescent substances, stopping the output
of the signal from the scanning circuit to the display panel, and then stopping
supply of power to the scanning circuit.
The power is preferably supplied from an auxiliary power source in performing
control when the voltage abnormality is observed.
In each of the above-described inventions, a time during which the signal output
to the display panel is stopped, or a time during which application of the acceleration
potential is stopped, or the delay time is a predetermined time. The predetermined
time is selected by counting a predetermined number of sync signals, or obtained
by counting the predetermined time with a timer.
Each invention can be preferably employed especially when the electron source
comprises a plurality of row-direction wiring lines for receiving a scanning signal,
a plurality of column-direction wiring lines for receiving a modulation signal,
and a plurality of electron-emitting devices connected to the row-direction wiring
lines and the column-direction wiring lines.
Each invention can be preferably employed especially when the acceleration potential
for accelerating electrons from the electron source is a potential higher by not
less than 500 V than a potential applied to emit electrons in the electron source.
In this case, the potential applied to emit electrons in the electron source is,
e.g., a potential applied to an electron-emitting portion. For example, in an electron-emitting
device which receives a potential difference between electrodes to emit electrons,
the potential applied to emit electrons is a lower potential applied to the one
of the electrodes which receive the potential difference.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
a scanning circuit for supplying a scanning signal to the display panel, a modulation
circuit for supplying a modulation signal to the display panel, and a control circuit
for stopping output from the scanning circuit and/or the modulation circuit to
the display panel until a signal output from the scanning circuit and/or the modulation
circuit to the display panel is determined in starting image display by outputting
a signal from the scanning circuit and/or the modulation circuit to the display panel.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
a scanning circuit for supplying a scanning signal to the display panel, a modulation
circuit for supplying a modulation signal to the display panel, and a control circuit
for delaying output of a signal from the scanning circuit and/or the modulation
circuit to the display panel after a power source is turned on in starting image
display by outputting a signal from the scanning circuit and/or the modulation
circuit to the display panel, wherein the signal output from the scanning circuit
and/or the modulation circuit to the display panel is determined during the delay time.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
an acceleration potential supply circuit for supplying to the display panel an
acceleration potential for accelerating electrons from the electron source, a scanning
circuit for supplying a scanning signal to the display panel, a modulation circuit
for supplying a modulation signal to the display panel, and a control circuit for
stopping supply of the acceleration potential until a signal output from the scanning
circuit and/or the modulation circuit to the display panel is determined in starting
image display by outputting a signal from the scanning circuit and/or the modulation
circuit to the display panel.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
an acceleration potential supply circuit for supplying to the display panel an
acceleration potential for accelerating electrons from the electron source, a scanning
circuit for supplying a scanning signal to the display panel, a modulation circuit
for supplying a modulation signal to the display panel, and a control circuit for
delaying supply of the acceleration potential after a power source is turned on
in starting image display by outputting a signal from the scanning circuit and/or
the modulation circuit to the display panel, wherein the signal output from the
scanning circuit and/or the modulation circuit to the display panel is determined
during the delay time.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
a scanning circuit for supplying a scanning signal to the display panel, a modulation
circuit for supplying a modulation signal to the display panel, and a control circuit
for stopping output from the scanning circuit and/or the modulation circuit to
the display panel until a power source voltage of the scanning circuit and/or the
modulation circuit reaches a desired value in starting image display by outputting
a signal from the scanning circuit and/or the modulation circuit to the display panel.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
a scanning circuit for supplying a scanning signal to the display panel, a modulation
circuit for supplying a modulation signal to the display panel, and a control circuit
for delaying output of a signal from the scanning circuit and/or the modulation
circuit to the display panel after a power source is turned on in starting image
display by outputting a signal from the scanning circuit and/or the modulation
circuit to the display panel, wherein a power source voltage of the scanning circuit
and/or the modulation circuit reaches a desired value during the delay time.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
an acceleration potential supply circuit for supplying to the display panel an
acceleration potential for accelerating electrons from the electron source, a scanning
circuit for supplying a scanning signal to the display panel, a modulation circuit
for supplying a modulation signal to the display panel, and a control circuit for
stopping supply of the acceleration potential until a power source voltage of the
scanning circuit and/or the modulation circuit reaches a desired value in starting
image display by outputting a signal from the scanning circuit and/or the modulation
circuit to the display panel.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
an acceleration potential supply circuit for supplying to the display panel an
acceleration potential for accelerating electrons from the electron source, a scanning
circuit for supplying a scanning signal to the display panel, a modulation circuit
for supplying a modulation signal to the display panel, and a control circuit for
delaying supply of the acceleration potential after a power source is turned on
in starting image display by outputting a signal from the scanning circuit and/or
the modulation circuit to the display panel, wherein a power source voltage of
the scanning circuit and/or the modulation circuit reaches a desired value during
the delay time.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
an acceleration potential supply circuit for supplying to the display panel an
acceleration potential for accelerating electrons from the electron source, a scanning
circuit for supplying a scanning signal to the display panel, a modulation circuit
for supplying a modulation signal to the display panel, and a control circuit for
stopping output of a signal from the scanning circuit and/or the modulation circuit
to the display panel, and then stopping supply of power to the scanning circuit
and/or the modulation circuit in turning off a power source while an image is displayed
by outputting a signal from the scanning circuit and/or the modulation circuit
to the display panel.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
an acceleration potential supply circuit for supplying to the display panel an
acceleration potential for accelerating electrons from the electron source, a scanning
circuit for supplying a scanning signal to the display panel, a modulation circuit
for supplying a modulation signal to the display panel, and a control circuit for
stopping output of a signal from the scanning circuit and/or the modulation circuit
to the display panel, and then stopping supply of power to the scanning circuit
and/or the modulation circuit in performing emergency shutdown while an image is
displayed by outputting a signal from the scanning circuit and/or the modulation
circuit to the display panel.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
an acceleration potential supply circuit for supplying to the display panel an
acceleration potential for accelerating electrons from the electron source, a scanning
circuit for supplying a scanning signal to the display panel, a modulation circuit
for supplying a modulation signal to the display panel, and a control circuit for
stopping output of a signal from the scanning circuit and/or the modulation circuit
to the display panel, and then stopping supply of power to the scanning circuit
and/or the modulation circuit when a voltage abnormality is observed while an image
is displayed by outputting a signal from the scanning circuit and/or the modulation
circuit to the display panel.
According to still another invention of the present application, an image
display apparatus is characterized by comprising a display panel for displaying
an image by irradiation with electrons from an electron source to fluorescent substances,
an acceleration potential supply circuit for supplying to the display panel an
acceleration potential for accelerating electrons from the electron source, a scanning
circuit for supplying a scanning signal to the display panel, a modulation circuit
for supplying a modulation signal to the display panel, a first power source for
supplying power to the acceleration potential supply circuit and/or the scanning
circuit and/or the modulation circuit, and a second power source for supplying
power to the scanning circuit and/or the modulation circuit upon an abnormal state.
In this case, the abnormal state is emergency shutdown, and the second power source
comprises a capacitor or a battery.
Each of the above-described inventions does not exclude an arrangement in which
the scanning circuit and/or the modulation circuit and/or the acceleration potential
supply circuit also serves as the control circuit.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a block diagram showing the driving circuit of an image display apparatus;
FIG. 2 is a block diagram showing an NTSC-RGB decoder unit;
FIG. 3 is a block diagram showing an analog processing unit;
FIG. 4 is a block diagram showing another arrangement of the first embodiment;
FIG. 5 is a timing chart for explaining the operation of a display panel driving circuit;
FIG. 6 is a block diagram showing a power source line layout;
FIG. 7 is a block diagram showing the flow of a control signal for controlling
supply of power;
FIG. 8 is a circuit diagram showing a power source circuit and power source
monitoring circuit;
FIG. 9 is a flow chart according to the first embodiment;
FIG. 10 is a flow chart according to the second embodiment;
FIG. 11 is a flow chart according to the third embodiment;
FIG. 12 is a flow chart according to the fourth embodiment;
FIG. 13 is a flow chart according to the fifth embodiment;
FIG. 14 is a flow chart according to the sixth embodiment;
FIG. 15 is a flow chart according to the seventh embodiment;
FIG. 16 is a perspective view showing a display panel;
FIG. 17 shows views of the layouts of fluorescent substances;
FIG. 18 shows a plan view and sectional view of a flat surface-conduction type
electron-emitting device;
FIG. 19 shows sectional views of the steps in manufacturing a flat surface-conduction
type electron-emitting device;
FIG. 20 is a waveform chart showing a forming voltage;
FIG. 21 shows waveform charts of an application voltage for electrification
activation processing;
FIG. 22 is a sectional view showing a stepped surface-conduction type electron-emitting device;
FIG. 23 shows sectional views of the steps in manufacturing a stepped surface-conduction
type electron-emitting device;
FIG. 24 is a graph showing the characteristics of an electron-emitting device;
FIG. 25 is a plan view showing a multi electron beam source;
FIG. 26 is a sectional view showing the multi electron beam source taken along
the line B-B′;
FIG. 27 is a block diagram showing a multifunctional display panel;
FIG. 28 is a plan view showing a conventional surface-conduction type electron-emitting device;
FIG. 29 is a sectional view showing a conventional field emission type electron-emitting device;
FIG. 30 is a sectional view showing a conventional MIM type electron-emitting
device; and
FIG. 31 is a circuit diagram showing the layout of electron-emitting devices
that has been examined by the present inventor to find a problem.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The best mode for carrying out the present invention will be described with reference
to the accompanying drawings.
First Embodiment
FIG. 1 is a block diagram showing a driving circuit for an SED (Surface Electron
emitter Display) panel according to this embodiment.
Reference symbol P2000 denotes a display panel. In this embodiment,
the display panel P2000 is constituted by arranging 240*720 surface-conduction
type devices; P2001 in a matrix by row wiring lines of 240 vertical rows
and column wiring lines of 720 horizontal columns. An electron beam emitted by
each surface-conduction type device; P2001 is accelerated by a high voltage
applied from a high-voltage power source unit; P30 to irradiate fluorescent
substances (not shown), thereby emitting light. The fluorescent substance (not
shown) can take various color layouts in accordance with application purposes.
For example, the fluorescent substance takes a vertically striped color layout
of R, G, and B colors.
This embodiment will exemplify an application of displaying an NTSC television
image on a display panel having pixels of 240 horizontal (R, G, and B trio)*240
vertical lines. Almost the same arrangement can cope with not only the NTSC image
but also image signals having different resolutions and frame rates, such as a
high-resolution HDTV image and computer output image.
The driving circui
