A driving method for an electron beam-generating apparatus having an electron source having a plurality of electron-emitting devices, and a plurality of modulation means for modulating electron beams emitted from the electron source in correspondence with information signals comprises applying a cut-off voltage to a first modulation means adjacent to a second modulation means to which an ON voltage is applied as the information signals in modulation of the electron beam.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a method for driving an electron 
beam-generating apparatus for formation of a pattern of emitted electron 
beams in correspondence with information signals. The present invention 
also relates to a method of driving an image-forming apparatus for 
formation of an image with a pattern of emitted electron beams. The 
present invention further relates to an electron beam-generating apparatus 
and an image-forming apparatus which are driven by the above driving 
methods. 
2. Related Background Art 
In recent years, research and development are being made actively and 
extensively regarding image-forming apparatuses which employ an electron 
source having a plurality of electron-emitting devices wired in a matrix 
state: especially, thin flat display apparatuses which employ the above 
devices. FIG. 3 illustrates schematically an example of one device unit of 
such an image-forming apparatus. 
The image-forming apparatus illustrated in FIG. 3 comprises a plurality of 
electron-emitting devices "A" arranged in a plane state on a substrate 31, 
and the electron-emitting devices A are connected to wiring electrodes 
32a, 32b corresponding to respective scanning lines. Above the substrate 
31, modulation electrodes 33 are arranged so as to form an XY matrix with 
the scanning lines, and modulate the electron beam emission of each device 
in accordance with information signals. The modulation electrode 33 has 
openings 34 for passage of the electron beams. 
The image-forming apparatus shown in FIG. 3 is usually driven as follows. A 
voltage for electron emission is applied to each of the electron-emitting 
devices A on one scanning line. Modulation voltages (ON/OFF voltages or 
gradation voltages for electron beams) are applied to modulation 
electrodes 33 in accordance with information signals for one scanning line 
of an image. Thereby a pattern of emitted electrons passing through the 
openings 34 is formed for the one line. The pattern of the emitted 
electrons is irradiated onto an image-forming member 35 to form one line 
of the image thereon. This process is successively conducted for each of 
the scanning lines for the image to form an entire picture image. If the 
image-forming member 35 is made of a luminescent material, the image is 
displayed by a plurality of luminous spots 36. 
Conventional methods for driving such an image-forming apparatus as 
mentioned above which has an electron source constituted of 
electron-emitting regions arranged in high density involve disadvantages 
such that the modulation voltages of adjacent electron beams affect each 
other to deflect electron beam trajectories and to change size and shape 
of the spots formed on the image-forming member face, thereby lowering the 
fineness of the formed image. 
FIG. 4 shows a disadvantage of a conventional driving method. In FIG. 4, 
three electron beams are emitted respectively from electron-emitting 
regions 40a, 40b, 40c for one scanning line, and the electron beams are 
modulated by modulation electrodes 41a, 41b, 41c. In the case where a 
positive voltage (ON voltage) is applied to the modulation electrodes, 
electron beams are irradiated from the electron-emitting regions 40a, 40b, 
40c onto the corresponding luminescent members (image-forming members) 
42a, 42b, 42c. If the electron-emitting regions are close to each other 
(high density arrangement), the respective electron beams 44 are deflected 
and spread after passing through the electron beam passage opening 43, by 
the forces "f" caused by adjacent modulation electrodes, and the spots 
spread undesirably on each of the luminescent members. 
In FIG. 5, three electron beams are emitted from the electron-emitting 
regions 50a, 50b, 50c for one scanning line, and the electron beams are 
modulated by the modulation electrodes 51a, 51b, 51c. In the case where a 
positive voltage (ON voltage) is applied to the modulation electrodes 51b 
and 51c and a negative voltage (cut-off voltage) to the modulation 
electrode 51a respectively, the electron beams 54 from the 
electron-emitting regions 50b, 50c pass through the electron passage 
openings 53, and thereafter the trajectories of the respective electron 
beams 54 are deflected by the forces "f" exerted by the adjacent 
modulation electrodes 51b, 51c, as shown in FIG. 5, and the spots formed 
on the luminescent members 52b, 52c are asymmetric. 
As shown in the above example, in the conventional driving method for an 
image-forming apparatus employing an electron source in which a plurality 
of electron-emitting regions are arranged, each electron beam emission 
pattern for the scanning line varies in electron beam trajectories, spot 
sizes, and spot shapes, which makes difficult the formation of fine, 
sharp, high-contrast images. This problem is serious, in particular, in 
color image-forming apparatus in which red, blue, and green luminescent 
members are sequentially arranged as image-forming members, because the 
aforementioned variation in electron beam trajectories, spot sizes, and 
spot shapes causes collision of the electron beams against luminescent 
members of unintended colors to give a less reproducible image of lower 
color purity and color tone irregularity, which makes it impossible to 
high density arrangement of the luminescent members. The above 
disadvantage is much more serious when the voltage (ON voltage) of the 
modulation electrode is raised in order to increase the quantity of 
electrons reaching the image-forming member. Therefore, it is 
impracticable to increase sufficiently the quantity of the electron 
irradiation onto the image-forming member and to raise the luminance and 
the contrast of the image as desired. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide a driving method for an 
image-forming apparatus and an electron beam-generating apparatus to 
obtain an image with high fineness, high sharpness, and high contrast. 
Another object of the present invention is to provide a driving method for 
an image-forming apparatus and an electron beam-generating apparatus to 
obtain a full-color image with extremely less irregularity of color tone 
with high color reproducibility. 
According to an aspect of the present invention, there is provided a 
driving method for an electron beam-generating apparatus having an 
electron source having a plurality of electron-emitting devices, and a 
plurality of modulation means for modulating electron beams emitted from 
the electron source in correspondence with information signals, the 
driving method comprising applying a cut-off voltage to a first modulation 
means adjacent to a second modulation means to which an ON voltage is 
applied as the information signals in modulation of the electron beam. 
According to a further aspect of the present invention, there is provided 
an electron beam-generating apparatus having an electron source having a 
plurality of electron-emitting devices, and a plurality of modulation 
means for modulating electron beams emitted from the electron source in 
correspondence with information signals, which is driven by the method 
stated in the preceding paragraph. 
According to another aspect of the present invention there is provided a 
driving method for an electron beam-generating apparatus having an 
electron source having a plurality of electron-emitting devices, and a 
plurality of modulation means for modulating electron beams emitted from 
the electron source in correspondence with information signals, the 
driving method comprising dividing information signals into a plurality of 
portions and inputting each of the portions to the modulation means 
successively in modulation of the electron beams. 
According to a further aspect of the present invention, there is provided 
an electron beam-generating apparatus having an electron source having a 
plurality of electron-emitting devices, and a plurality of modulation 
means for modulating electron beams emitted from the electron source in 
correspondence with information signals, which is driven by the method 
stated in the preceding paragraph. 
According to still another aspect of the present invention, there is 
provided a driving method for an electron beam-generating apparatus having 
an electron source having a plurality of electron-emitting devices, and a 
plurality of modulation means for modulating electron beams emitted from 
the electron source in correspondence with-information signals, the 
driving method comprising dividing information signals into a plurality of 
portions and inputting each of the portions to the modulation means at 
intervals of n rows (n.gtoreq.1) of the modulation means successively 
"n+1" times, and inputting cut-off signals to other rows of the modulation 
means to which information signals are not being inputted. 
According to a further aspect of the present invention, there is provided 
an electron beam-generating apparatus having an electron source having a 
plurality of electron-emitting devices, and a plurality of modulation 
means for modulating electron beams emitted from the electron source in 
correspondence with information signals, which is driven by the method 
stated in the preceding paragraph. 
According to a further aspect of the present invention, there is provided a 
driving method for an image-forming apparatus having an electron source 
having a plurality of electron-emitting devices, a plurality of modulation 
means for modulating electron beams emitted from the electron source in 
correspondence with information signals, and an image-forming member for 
forming an image by irradiation of modulated electron beams, the driving 
method comprising applying a cut-off voltage to a first modulation means 
adjacent to a second modulation means to which an ON voltage is applied as 
the information signals in modulation of the electron beams. 
According to a further aspect of the present invention, there is provided 
an image-forming apparatus having an electron source having a plurality of 
electron-emitting devices, a plurality of modulation means for modulating 
electron beams emitted from the electron source in correspondence with 
information signals, and an image-forming member for forming an image on 
irradiation of modulated electron beams, which is driven by the driving 
method stated in the preceding paragraph. 
According to a further aspect of the present invention, there is provided a 
driving method for an image-forming apparatus having an electron source 
having a plurality of electron-emitting devices, a plurality of modulation 
means for modulating electron beams emitted from the electron source in 
correspondence with information signals, and an image-forming member for 
forming an image on irradiation of modulated electron beams, the driving 
method comprising dividing information signals into a plurality of 
portions and inputting each of the portions to the modulation means 
successively in modulation of the electron beams. 
According to a further aspect of the present invention, there is provided 
an image-forming apparatus having an electron source having a plurality of 
electron-emitting devices, a plurality of modulation means for modulating 
electron beams emitted from the electron source in correspondence with 
information signals, and an image-forming member for forming an image on 
irradiation of modulated electron beams, which is driven by the driving 
method stated in the preceding paragraph. 
According to a still further aspect of the present invention, there is 
provided a driving method for an image-forming apparatus having an 
electron source having a plurality of electron-emitting devices, a 
plurality of modulation means for modulating electron beams emitted from 
the electron source in correspondence with information signals, and an 
image-forming member for forming an image on irradiation of modulated 
electron beams, the driving method comprising dividing information signals 
into a plurality of portions and inputting each of the portions to the 
modulation means at intervals of n rows (n.gtoreq.1) of the modulation 
means fractionally and successively "n+1" times, and inputting cut-off 
signals to other rows of the modulation means to which information signals 
are not being inputted. 
According to a further aspect of the present invention, there is provided 
an image-forming apparatus having an electron source having a plurality of 
electron-emitting devices, a plurality of modulation means for modulating 
electron beams emitted from the electron source in correspondence with 
information signals, and an image-forming member for forming an image on 
irradiation of modulated electron beams, which is driven by the driving 
method stated in the preceding paragraph.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention is described below in more detail. 
FIG. 3 shows, as an example, an apparatus in which electron-emitting device 
lines (X.sub.1, X.sub.2, . . . ) having respectively a plurality of 
electron-emitting devices A, and modulation electrodes (Y.sub.1, Y.sub.2, 
. . . ) are arranged to form an XY matrix (or in rows and columns) with 
the electron-emitting device lines. With this apparatus, a voltage Vf for 
electron emission is applied to one of the electron beam-emitting device 
lines (X.sub.1, X.sub.2, . . . ), and voltages are applied to the 
modulation electrodes (Y.sub.1, Y.sub.2, . . . ) in correspondence with 
information signals for the one device line to form an electron emission 
pattern for the one device line of information signals. This procedure is 
conducted successively for the respective electron-emitting device lines 
to form an electron beam emission pattern for a picture image. An image is 
formed by irradiation of the electron-beam emission pattern onto the 
image-forming member 35. 
In the driving method of the present invention, in application of voltage 
to the modulation electrodes (Y.sub.1, Y.sub.2, . . . ) in correspondence 
with information signals, a cut-off voltage is applied to modulation 
electrodes (e.g., Y.sub.1 and Y.sub.3) adjacent to the ON voltage-applied 
modulation electrode (e.g., Y.sub.2) irrespectively of the information 
signals. In such a driving method, the electron beams irradiated by an ON 
voltage onto the image-forming member are not adversely affected by the 
voltage applied to the adjacent modulation electrodes. 
In an example of the aforementioned driving method of the present 
invention, information signals are inputted to the modulation electrodes 
at intervals of n rows of the modulation electrodes (n.gtoreq.1) 
divisionally and successively "n+1" times, and cut-off signal is inputted 
to other rows of the modulation electrodes to which no information signal 
is inputted. 
FIG. 1 shows an example of a driving method of the device of FIG. 3 at n=1. 
In FIG. 1, the information signals are inputted to odd-numbered rows of 
modulation electrodes and even-numbered ones divisionally two times, and 
cut-off signals are inputted to the modulation electrodes to which no 
information signal is inputted. For example, the voltage Vf necessary for 
electron emission is applied to the X.sub.2 -th line of the 
electron-emitting devices. For inputting the information signals to the 
modulation electrodes (Y.sub.1, Y.sub.2, Y.sub.3, . . . ), (1) firstly 
information signals are inputted to Y.sub.2m+1 -th modulation electrodes 
(m=0, 1, 2, . . . ) and cut-off signals are inputted to Y.sub.2m+2 -th 
modulation electrodes, respectively, and (2) then information signals are 
inputted to Y.sub.2m+2 -th modulation electrodes and cut-off signals are 
inputted to Y.sub.2m+1 -th modulation electrodes, respectively. Thereby an 
electron beam emission pattern is formed corresponding to the information 
signals for the X.sub.2 -th line. The above procedure is conducted 
successively for each of the electron-emitting device lines to form an 
electron beam-emission pattern for a picture image. A picture image is 
formed on an image-forming member by irradiating the above electron beam 
emission pattern thereon. 
FIG. 2 shows another example where the value of n is 2 in the device of 
FIG. 3. In FIG. 2, the information signals are inputted divisionally at 
intervals of two rows of modulation electrodes three times. In each time, 
cut-off signals are inputted to the modulation electrodes to which 
information signals are not inputted. For example, the voltage Vf for 
electron emission is applied to X.sub.2 -th line of the electron-emitting 
devices. For inputting the information signals to the modulation 
electrodes, (1) firstly information signals are inputted to Y.sub.3m+1 -th 
rows of the modulation electrodes, and cut-off signals are inputted to 
Y.sub.3m+2 -th and Y.sub.3m+3 -th rows of modulation electrodes, 
respectively, and (2) then information signals are inputted to Y.sub.3m+2 
-th rows of modulation electrodes and cut-off signals are inputted to 
Y.sub.3m+1 -th and Y.sub.3m+3 -th rows of modulation electrodes, 
respectively, and (3) finally information signals are inputted to 
Y.sub.3m+3 -th rows of modulation electrodes and cut-off signals are 
inputted to Y.sub.3m+1 -th and Y.sub.3m+2 -th rows of modulation 
electrodes, respectively. Thereby electron beam emission pattern is formed 
corresponding to the information signals for the X.sub.2 -th 
electron-emitting device line. The above procedure is conducted 
successively for each of the electron-emitting device lines to form an 
electron beam-emission pattern for a picture image. A picture image is 
formed on an image-forming member by irradiating the above electron beam 
emission pattern thereon. 
A suitable voltage is applied to the image-forming member in order to 
irradiate effectively the electron beam pattern emitted from the electron 
source. The magnitude of this voltage is suitably selected depending on 
the ON voltage, the cut-off voltage, and the kind of the electron-emitting 
device employed. 
The aforementioned information signals (or modulation signals) include an 
ON signal which allows the irradiation of an electron beam onto the 
image-forming member in an amount of larger than a certain level, and a 
cut-off signal which shuts out the irradiation of an electron beam onto 
the image-forming member. If gradation of the display is desired, the 
information signals include also gradation signals which vary the quantity 
of the electron beam irradiation onto the image-forming member. The ON 
signal and the cut-off signal are suitably selected depending on the kind 
of the electron-emitting device, the voltage applied to the image-forming 
member, and so forth. 
The electron beam-generating apparatus or the image-forming apparatus which 
is driven according to the driving method of the present invention may 
comprise a full-color image-forming member in which fluorescent member of 
red (R), green (G), and blue (B) are arranged. 
Preferred examples of modulation means and electron-emitting devices of the 
apparatus are described below in which the driving method of the present 
invention is suitably employed. 
Firstly, an example of a particularly preferred modulation means for the 
electron-generating apparatus and the image-forming apparatus is described 
below. 
FIG. 6 illustrates an embodiment in which electron-emitting devices A and 
modulation electrodes 3 are both provided on one and the same face of a 
substrate 1, and FIG. 7 illustrates another embodiment in which 
electron-emitting devices A are provided on an insulating substrate 1 and 
modulation electrodes are laminated on the reverse face of the substrate 
1. In these embodiments, electron-emitting device lines having 
respectively a plurality of electron-emitting regions between wiring 
electrodes 2a, 2b, and modulation electrodes 3 are arranged in an XY 
matrix. FIG. 8 shows an embodiment called simple matrix construction 
generally, in which a plurality of electron-emitting devices A are 
arranged in a matrix and each of the devices is connected with a signal 
wiring electrode 3b and a scan-wiring electrode 3a. 
The modulation means for any of the above three embodiments does not 
require strict positional registration as that required in the modulation 
electrodes shown in FIG. 3 between an electron-emitting region and an 
electron passage opening 34, and therefore does not cause irregularity of 
luminance in luminous image like that caused by positional deviation of 
the electron passage opening from the electron-emitting region. 
In the devices employing the driving method of the present invention, the 
type of the electron-emitting devices are not specially limited, but cold 
cathode type devices are preferred. In the case where a plurality of hot 
cathodes are employed, uniform electron emission characteristics in a 
large area are not obtainable since electron emission characteristics of 
the hot cathode are affected by temperature distribution. Further, as the 
electron-emitting devices, surface conduction type electron-emitting 
devices are preferred in the present invention. 
The surface conduction type electron-emitting devices are known, and is 
exemplified by a cold cathode device disclosed by M. I. Elinson, et al. 
(Radio Eng. Electron Phys. Vol. 10, pp. 1290-1296 (1965)). This device 
utilizes the phenomenon that electrons are emitted from a thin film of 
small area formed on a substrate on application of electric current in a 
direction parallel to the film face. The surface conduction type 
electron-emitting device, in addition to the above-mentioned one disclosed 
by Elinson et al. employing SnO.sub.2 (Sb) thin film, includes the one 
employing an Au thin film (G. Dittmer: "Thin Solid Films", Vol. 9, p. 317 
(1972)), the one employing an ITO thin film (M. Hartwell, and C. G. 
Fonstad: "IEEE Trans. ED Conf.", p. 519 (1983)), and so forth. 
FIG. 9 illustrates a typical device constitution of such surface conduction 
type electron-emitting devices. The device in FIG. 9 comprises electrodes 
22, 23 for electric connection, a thin film 25 formed of an 
electron-emitting substance, a substrate 21, and an electron-emitting 
region 24. Conventionally, in such a surface conduction type 
electron-emitting device, the electron-emitting region is formed by a 
voltage application treatment, called "forming", of an emitting region 
prior to use for electron emission. The forming is a treatment of flowing 
electric current through the thin film 25 by application of a voltage 
between the electrodes 22, 23, thereby the emitting region-forming thin 
film being locally destroyed, deformed, or denatured by the generated 
Joule's heat to form the electron-emitting region 24 in a state of high 
electric resistance. Here, the state of high electric resistance means a 
discontinuous state of a part of the thin film 25 in which cracks having 
an "island structure" therein are formed. The portion of the thin film in 
such a state is spatially discontinuous but is continuous electrically. 
The surface conduction type electron-emitting device emits electrons, when 
voltage is applied between the electrodes 22, 23 to allow electric current 
to flow through the highly resistant discontinuous film on the surface of 
the device surface. 
The inventors of the present invention disclosed, in Japanese Patent 
Application Laid-Open Nos. 1-200532 and 2-56822, a novel surface 
conduction type electron-emitting device in which fine particles for 
emitting electrons are disposed in dispersion between electrodes. The 
inventors of the present invention later found that the above surface 
conduction type electron-emitting device is particularly excellent in the 
electron emission efficiency, the stability of the emitted electrons, and 
so forth, when the dispersed fine particles have an average particle 
diameter in the range of from 5 .ANG. to 300 .ANG., and the intervals of 
the fine particles are in the range of from 5 .ANG. to 100 .ANG.. Such a 
type of surface conduction type electron-emitting devices having dispersed 
fine particles have advantages of (1) high electron emission efficiency, 
(2) simple structure and ease of production, (3) possibility of 
arrangement of a large number of devices on one substrate, and so forth. 
FIG. 10 shows a typical device constitution of the surface conduction type 
electron-emitting device. In FIG. 10, the device comprises device 
electrodes for electric connection 22, 23, electron-emitting region 27 in 
which fine particles 26 for emitting electrons are disposed in dispersion, 
and a substrate 21. 
The present invention is described below in more detail by reference to 
Examples. 
EXAMPLE 1 
The device driven according to the present invention in this Example was an 
image-forming apparatus having surface conduction type electron-emitting 
devices and was driven as described below. 
Preparation Example of Image-Forming Apparatus! 
The method for preparation of the image-forming apparatus is explained by 
reference to FIGS. 11 and 12. 
(1) Device electrodes 61a, 61b, and wiring electrodes 62a, 62b were formed 
on a glass substrate as the insulating substrate 60. The electrodes were 
formed from metallic nickel in this Example, but the material therefor is 
not limited provided that it is electroconductive. The gap between the 
electrodes 61a, 61b was 2 .mu.m, and the pitch of the wiring electrodes 
62a, 62b was 0.5 mm. 
(2) Organic palladium (CCP-4230, made by Okuno Seiyaku K.K.) was applied 
between the electrodes 61a, 61b, and the applied matter was baked at 
300.degree. C. for one hour to form a fine particle film 63 composed of 
palladium oxide. 
(3) Above the substrate 60, the modulation electrodes 64 having electron 
passage openings 65 were placed and fixed in an XY matrix so as to be 
perpendicular to the wiring electrodes 62a, 62b. 
(4) A face plate 68 having a transparent electrode 66 and a fluorescent 
member 67 on its inside face was placed 4 mm above the substrate 60 by aid 
of a supporting frame 69. Frit glass was applied to the joint portion 
between the supporting frame 69 and the face plate 68, and was baked at 
430.degree. C. for more than 10 minutes. 
(5) The enclosure prepared as above (constituted of the substrate 60, the 
supporting frame 69, and the face plate 68) was evacuated by a vacuum pump 
to a sufficient vacuum degree (preferably from 10.sup.-6 torr to 10.sup.-7 
torr). Then voltage pulse of a desired waveform was applied between the 
wiring electrodes 62a, 62b to form electron emitting regions 70 between 
the device electrodes 61a, 61b. The pitch of the electron-emitting region 
was made to be 0.5 mm. The fine particles in the electron-emitting region 
had an average particle diameter of 100 .ANG., and the interval between 
the particles was 20 .ANG. according to SEM observation. 
The image-forming apparatus was prepared as above which comprises an 
electron source having electron-emitting devices arranged in a matrix. 
With this apparatus, at a voltage of from 5 to 10 kV applied to the 
transparent electrode 66, cut-off control was practicable at a voltage of 
the modulation electrode 64 of -30 V or more negative voltage; ON control 
was practicable at a voltage thereof of zero volt or higher; and 
gradational display was practicable by continuously changing the quantity 
of the electrons of p the emitted electron beam in the range of from -30 V 
to 0 V. In FIG. 11, the numeral 71 denotes luminous spots of the 
fluorescent member. 
Example of Device-Driving Method! 
The method of driving the device of the present invention is explained by 
reference to FIG. 13 for the case where scanning is conducted from the 
electron-emitting device line of M=1: 
(1) A constant voltage is applied to the transparent electrode 66 (FIG. 11) 
by a voltage application means (not shown in the drawing), and electron 
emission voltage Vf is applied to the electron-emitting device line (or 
scanning line) of M=1. 
(2) Of the information signals for the scanning line of M=1, information 
signals to be inputted to even-numbered modulation electrodes (N=2, 4, . . 
. ) are stored in a memory 80, while the information signals to be 
inputted to odd-numbered modulation electrodes (N=1, 3, 5, . . . ) are 
inputted directly thereto by a voltage application means 81 as modulation 
voltages (Vm.sub.1, Vm.sub.3, Vm.sub.5, . . . ) including ON voltages, 
cut-off voltages and gradation voltages in corresponding with the 
information signals. During this period, a cut-off voltage (V.sub.off) is 
applied to the even-numbered modulation electrodes (N=2, 4, . . . ) 
irrespectively of the information signals according to cut-off the signals 
sent out from the signal switching circuit (signal separation means) 82 to 
a voltage application means 83. 
(3) Then the signal switching circuit 82 switches the circuit so as to 
input, to the even-numbered modulation electrodes, the portion of the 
information signals for the scanning line (M=1) stored in the memory 80. 
Thereby modulation voltages (Vm.sub.2, Vm.sub.4, . . . ) including ON 
voltages, cut-off voltages and gradation voltages are inputted to 
even-numbered modulation electrodes through the voltage application means 
83 in correspondence with the information signals. During this period, a 
cut-off voltage (V.sub.off) is applied to the odd-numbered modulation 
electrodes (N=1, 3, 5, . . . ) irrespectively of the information signals 
according to cut-off the signals sent out from the signal switching 
circuit 82 to a voltage application means 81. 
As described above, the process of inputting information signals of one 
scanning line in two steps separately for odd-numbered modulation 
electrodes and even-numbered ones is conducted within the time of scanning 
of one line of display. 
The above steps of (1) to (3) are practiced for each scanning line 
sequentially to display one or more picture images on a fluorescent member 
face. 
According to the driving method of this Example, respective luminous spots 
forming an image display on the fluorescent member face were extremely 
uniform in size and shape, and gave extremely fine and sharp image without 
crosstalk. 
The modulation electrodes, which are arranged in as in FIG. 11 in this 
Example, may be the ones as shown in FIG. 6, or FIG. 7. With any 
embodiment of the modulation electrodes, a similar driving method as in 
this Example (FIGS. 14 and 15) gave an image displayed with spots of 
uniform and stable sizes and shapes with high fineness without crosstalk. 
In the embodiments of FIG. 6 and FIG. 7, at an application voltage of the 
transparent electrodes of from 5 to 10 kV, the electron beam could be cut 
off at the modulation voltage of -40 V or more negative voltage, turned on 
at 10 V or higher, continuously controlled between -40 V and 10 V for 
gradational display. 
EXAMPLE 2 
The image-forming apparatus in this Example was prepared in the same manner 
as in Example 1 except that the device electrodes 61a, 61b and the wiring 
electrodes 62 are arranged as shown in FIGS. 8 and 16, modulation 
electrodes of Example 1 was not provided, and fluorescent materials of red 
(R), green (G), and blue (B) were arranged in a black stripe constitution 
as shown in FIG. 18 such that one fluorescent material (R, G, or B) 
corresponds to one electron-emitting device. 
In this working example, instead of such a modulation electrode as used in 
Example 1, a signal-wiring electrode described later plays the same part 
as the transparent electrode does in Example 1. 
Example of Device-Driving Method! 
The method of driving the device of the present invention is explained by 
reference to FIG. 17 for the case where scanning is conducted from the 
electron-emitting device line of M=1: 
(1) A constant voltage is applied to the transparent electrode by a voltage 
application means (not shown in the drawing), and electron emission 
voltage Vf is applied to the electron emission line (or scanning line) of 
M=1. 
(2) Of the information signals for the scanning line of M=1, information 
signals to be inputted to green-displaying signal wiring electrodes G and 
blue-displaying signal wiring electrodes B are stored in a memory 80, 
while the information signals to be inputted to red-displaying signal 
wiring electrodes R are inputted directly thereto by a voltage application 
means 81 as modulation voltages (VmR) including ON voltages, cut-off 
voltages and gradation voltages in correspondence with the information 
signals. During this period, a cut-off voltage (V.sub.off) is applied to 
the signal wiring electrodes G and B irrespectively of the information 
signals according to cut-off the signals sent out from the signal 
switching circuit 82 to a voltage application means 83. 
(3) The signal switching circuit 82 switches the circuit so as to input, to 
the signal-wiring electrode G, the portion of the information signals 
stored in the memory 80 for the green-displaying information signal of the 
scanning line of M=1, and modulation voltages (VmG) including ON voltages, 
cut-off voltages and gradation voltages are inputted to the signal wiring 
electrode G through the voltage application means 81 in correspondence 
with the information signals. During this period, a cut-off voltage 
(V.sub.off) is applied to the signal-wiring electrodes R and B 
irrespectively of the information signals according to cut-off the signals 
sent out from the signal switching circuit 82 to the voltage application 
means 83. 
(4) The signal switching circuit 82 switches the circuit so as to input, to 
the signal-wiring electrode B, the portion of the information signals 
stored in the memory 80 for the blue-displaying information signal of the 
scanning line of M=1, and modulation voltages (VmB) including ON voltages, 
cut-off voltages and gradation voltages are inputted to the signal wiring 
electrode B through the voltage application means 81 in correspondence 
with the information signals. During this period, a cut-off voltages 
(V.sub.off) is applied to the signal-wiring electrodes R and G 
irrespectively of the information signals according to cut-off the signals 
sent out from the signal switching circuit 82 to the voltage application 
means 83. 
As described above, the process of inputting information signals of one 
scanning line at intervals of two signal-wiring electrodes in three steps 
for three colors separately is conducted within the time of scanning of 
one line of display. 
As realized from the above description, the application of the modulation 
voltage to the signal-wiring electrode in the present working example 
corresponds to the application of voltage to the modulation electrode in 
Example 1. 
The above steps of (1) to (4) are practiced for each scanning line 
successively to display a full-color picture image on a fluorescent member 
face. 
According to the driving method of this Example, respective luminous spots 
forming an image display on the fluorescent member faces of each color 
were extremely uniform in size and shape, and gave a full-color image with 
improved color purity with excellent color reproducibility without 
crosstalk. 
The modulation electrodes, which are arranged as in FIGS. 8 and 16 in this 
Example, may be arranged as shown in FIG. 6, FIG. 7, or FIG. 11. With any 
embodiment of the modulation electrodes, a similar driving method as in 
this Example gave a full-color image with spots of uniform and stable 
sizes and shapes with improved color purity with excellent color 
reproducibility and without crosstalk. 
The image-forming apparatus of the present invention will possibly be 
useful widely in public and industrial application fields such as 
high-vision TV picture tubes, computer terminals, large-picture home 
theaters, TV conference systems, TV telephone systems, and so forth.