Flat panel type display and method for driving the display

Abstract: A flat panel type display comprising control electrodes each divided in the horizontal direction of the screen thereof and arranged in a vacuum casing, fluorescent material provided on each control electrode, mesh-like electrodes facing the fluorescent material, vertical scanning electrodes each facing the mesh-like electrodes and divided in the vertical direction of the screen thereof and an electron source for generating a plurality of electron beams continuously or discretely in the extension of space between a light emitting portion composed of the fluorescent material and a group of the vertical scanning electrodes in the horizontal direction of the screen thereof. Further, a partition made of insulating material is provided in the divided portion of each control electrode to increase the withstand voltage between each pair of the adjacent control electrodes, and a modulation signal is supplied to each control electrode. Alternatively, every n pieces of the control electrodes are connected to a bus to which a pulse voltage for causing the fluorescent material to emit light is applied. Furthermore, to a first vertical scanning electrode in the side, where an electron beam going straight on is incident, is applied a voltage, of which the magnitude (V D ) is equal to a voltage applied to the fluorescent screen or the mesh-like electrodes. Then, to a predetermined number of the vertical scanning electrodes subsequent to the first vertical scanning electrode in the direction in which the electron beam goes straight on, is applied a voltage of which the magnitude (V D -V CC ) is less than the voltage applied to the fluorescent screen. Thereafter, to a vertical scanning electrode subsequent to the predetermined number of the vertical scanning electrodes in the direction in which the electron beam goes straight on, is applied a voltage of which the magnitude (V D - V M ) is equal to or more than the voltage applied to the fluorescent screen or the mesh-like electrodes. Thus, the vertical scanning is performed.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention generally relates to a device for displaying a picture and more particularly to a flat panel type color display for use in a color television receiving device, a display terminal of a computer system and so on. 2. Description of the Related Art Document JP-A-60-115134 discloses a flat panel type display having a screen, comprising a scanning electrode, a modulation electrode group, a light emitting portion, an electrode source provided in an extension of space between said light emitting portion and said scanning electrode. In this flat panel type display the scanning electrode is divided into a plurality of stripe-like electrodes in order to achieve a uniform incident angle and spot diameter of an electron beam on the light emitting portion by sequentially switching and scanning the potential of each of the plurality of stripe-like electrodes. A typical example of a further conventional image tube is disclosed in the Japanese Patent Application Provisional Publication No. 56-76149 Official Gazette. Figs. 1 (A) and (B) are a section and a plan view of this image tube, respectively. As shown in these figures, this image tube is provided with a flat tube body 101 made of glass and so forth. On an inner surface 101a of this tube body 101, a plurality of stripe-like control electrodes 102 [102 1 , 102 2, 102 3 , ... 102 n ], the number of which is equal to that of pixels in the horizontal direction thereof, are arranged in parallel with each other at a predetermined interval. Further, on each of the stripe-like control electrodes 102, a fluorescent screen 104 composing a screen of the display is formed by coating the stripe-like control electrode with fluorescent material 103 suitable for a low velocity electron beam. Over the fluorescent screen 104, there is arranged a mesh-like electrode 107 facing the fluorescent screen 104 at a predetermined interval. Further, on another inner surface 101b of the tube body 101 facing the fluorescent screen 104, there is provided a main deflecting electrode 106 for deflecting a strip-like electron beam to the fluorescent screen 104 and making the electron beam scan the fluorescent screen 104 in the vertical direction as indicated by an arrow C in Fig. 1 (B). This main deflecting electrode 106 is made of a transparent conductive film. On the other hand, at the right side of the fluorescent screen 104, as viewed in Fig. 1 (A) (that is, in a bottom end in the longitudinal direction of each stripe-like control electrode 102, as viewed in Fig. 1 (B)), is arranged a beam source 108 for emitting a strip-like low velocity electron beam 105. The beam source 108 is composed of a cathode 109 stretched in the horizontal direction from left to right as viewed in Fig. (B) and made of tungsten, an electrode 111, to which a voltage substantially equal to a voltage applied to the cathode 109 is applied, enclosing this cathode 109 and having a slit 110 also extending in the horizontal direction from left to right as viewed in this figure and an accelerating electrode 113, to which a positive constant voltage is applied, having a narrow slit 112. Further, in front of the beam source 108, there is arranged an auxiliary deflecting electrode 114 comprised of a pair of electrode plates 114A and 114B for deflecting the strip-like electron beam 105 in cooperation with the main deflecting electrode 106. Next, an operation of the conventional device as above constructed will be described hereinafter. First, a nonmodulated strip-like electron beam emitted from the beam source 108 in parallel with the fluorescent screen 104 is deflected by the auxiliary deflecting electrode 114 and the main deflecting electrode 106 and is further incident on the fluorescent screen 104, and the fluorescent screen 104 is scanned at a constant speed by varying the extent of the deflection of the electrode beam in the vertical direction indicated by the arrow C in Fig. 1 (B). On the other hand, a video signal of one horizontal scanning interval is simultaneously supplied to each stripe-like control electrode 102. In this case, the video signal is sampled correspondingly to pixels positioned in the horizontal direction, that is, to the stripe-like control electrodes 102, and each of the sampled signals is serially supplied to each corresponding stripe-like control electrode 102. Thus, a video signal is fed to each stripe-like control electrode 102 every horizontal scanning interval. At that time the surface of the fluorescent material 103 provided on the each stripe-like control electrode 102 is irradiated with the strip-like electron beam 105, and parallel lines on the fluorescent screen 104 are serially excited by the scan of the strip-like electron beam 105 and emit light, thereby obtaining a desired image. However, the conventional device as above constructed has drawbacks that if the resolution power thereof is increased by dividing each stripe-like control electrode 102 among pixels, with the picture displaying area, which is available for displaying a picture or image, thereof unchanged, a pitch or interval between adjacent stripe-like control electrodes 102 becomes extremely small and a division width obtained by the division becomes narrower, that thus there has occurred a problem of a withstand voltage between stripe-like control electrodes 102, and further the voltage of the video signal applied to each stripe-like control electrode 102 cannot be sufficiently increased and consequently it becomes very difficult to obtain a light picture, that video signal processing circuits of the number, which is equal to that of the stripe-like control electrodes 102, is necessary, thereby increasing power consumption, and that an angle of incidence of the electron beam to the fluorescent screen 104 varies with the vertical scanning position of the electron beam, and the size of a beam spot in the vertical direction also changes. In addition, it is to be noted that there occur the reflection of the electron beams and the secondary emission of electrons by the fluorescent screen 104 and the mesh-like electrodes 107 when the electron beams are incident thereon. These reflected and secondary electrons are reflected and emitted at an angle of emission, the magnitude of which is nearly equal to an angle of incidence, to the fluorescent screen 104 and the mesh-like electrodes 107. Further, these reflected and emitted electrons are deflected by the electric field present between the main deflecting electrode 106 and the mesh-like electrode 107 and are incident once more on positions, which are not the same with the positions of the electron beams at the last incidence. This causes the fluorescent material 103 to unnecessarily emit light. Thus, the conventional device has another drawback that the contrast is reduced, and a ghost-like image is generated in the vertical direction of the screen of the display. The present invention is accomplished to eliminate the drawbacks of the conventional device. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a flat panel type display having a simple structure which can increase the withstand voltage between each pair of the adjacent control electrodes and can obtain even beam spots of electrons. Further, it is another object of the present invention to provide a flat panel type display wherein the re-incidence of the reflected electron beams and the secondary electrons, which are generated by the incidence of an electron beam on the electrodes, on the fluorescent screen is prevented. According to the invention this object is accomplished by a flat panel type display having a screen, control electrodes divided in a first direction of said screen and provided in a vacuum casing, a light emitting portion composed of fluorescent materials provided on said control electrodes, a mesh-like electrode provided in said casing and facing said fluorescent materials, scanning electrodes each divided in a second direction perpendicular to the first direction of said screen and facing said mesh-like electrode, and an electron source provided on the extension of the space between said light emitting portion and said scanning electrodes for generating electron beams uniformly or discretely in the first direction of said screen, said flat panel type display being characterized in that a partition made of insulating material is provided between each pair of adjacent divided portions of said control electrode. BRIEF DESCRIPTION OF THE DRAWINGS Other features, objects and advantages of the present invention will become apparent from the following description of preferred embodiments with reference to the drawings in which like reference characters designate like or corresponding parts throughout several views, and in which: Figs. 1 (A) and (B) are a vertical section and a plan view of a conventional flat panel type display, respectively; Figs. 2 (A), (B) and (C) are diagrams for showing the whole construction of a first example of a flat panel type display embodying the present invention; Fig. 3 is a diagram for showing the orbits of electron beams in the display of Fig. 2; Figs. 4 (A) and (B) are waveform charts for showing the waveforms of pulse voltage signals applied to scanning electrodes in the display of Fig. 2; Figs. 5 (A) and (B) are diagrams for showing the whole construction of a second example of a flat panel type display embodying the present invention; Fig. 6 is a waveform chart for showing the waveform of a pulse voltage signal applied to control electrodes; Fig. 7 is a sectional view of a third example of a flat panel type display embodying the present invention, for illustrating the condition of applying a voltage to each vertical scanning electrode, as well as the orbits of the electron beams; Fig. 8 is a graph for illustrating a model for obtaining the orbits of reflected electron beams of Fig. 7; Fig. 9 (A) is a perspective view of the display of Fig. 7; and Fig. 9 (B) (a)-(z) are time charts for showing the waveforms and various timings of voltage signals applied to each vertical scanning electrode. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail by referring to the accompanying drawings. First, referring to Figs. 2 to 4, a first example of a flat panel type display will be explained hereinbelow. Fig. 2 (A) is a side elevational view of this flat panel type display. Further, Fig. 2 (B) is a plan view taken on line B-B of Fig. 2 (A), and Fig. 2 (C) is a front view taken on line C-C of Fig. 2 (A). As shown in these figures, this flat panel type display is provided with a flat casing 1 made of glass and so forth. Furthermore, on an inner surface la of this casing 1, a plurality of stripe-like control electrodes 2, the number of which is equal to that of pixels in the horizontal direction thereof, are arranged in parallel with each other at a predetermined interval. Further, the top surface of each control electrode 2 is coated with fluorescent material 3 suitable for a low velocity electron beam. Furthermore, a fluorescent screen 5, that is a light emitting portion, is formed by providing partitions 4 made of insulating material such as low melting point flint glass. The thickness of the partition 4 is made larger than that of the fluorescent material 3. Over the fluorescent screen 5, there is arranged a mesh-like electrode 6 facing the fluorescent screen 5 at a predetermined interval or having openings bored at the positions corresponding to the control electrodes 2. Further, on another inner surface 1b of the casing 1 facing the fluorescent screen 5, there are provided vertical scanning electrodes 8 for deflecting a strip-like electron beam 7 to the fluorescent screen 5 and making the electron beam scan the fluorescent screen 5 in the vertical direction. Each vertical scanning electrode 8 is like a strip extending in the horizontal direction and is provided on the surface 1b in the horizontal direction at a predetermined interval. On the other hand, at the right side of the fluorescent screen 5, as viewed in Fig. 2 (A) (namely, in a bottom end in the longitudinal direction of each control electrode 2, as viewed in Fig. 2 (B)), there is arranged a beam source 9 for emitting a strip-like low velocity electron beam 7. The beam source 9 may be the beam source 108 used in the conventional device. Further, in case of this embodiment, an auxiliary deflecting electrode 10 is divided in the horizontal direction at a predetermined pitch. Next, an operation of the conventional device as above constructed will be described hereinafter. The strip-like electron beam 7 is emitted from the beam source 9 in such a manner to be in parallel with the fluorescent screen 5. However, when fabricating each electrode, it may occur that the central axis of the strip-like electron beam 7 at the time of being emitted by the beam source 9, the horizontal plane including the central axis of each vertical scanning electrode 8 and that including the central axis of each mesh-like electrode 6, which should be initially arranged to be in parallel with each other, are shifted from such initial relative positional relation in the horizontal direction. Thus, the voltage applied to each auxiliary deflecting electrode 10 divided in the horizontal direction is regulated such that the strip-like electron beam 7 is incident in the space between the vertical scanning electrodes 8 and the mesh-like electrode 6 uniformly in the horizontal direction. Further, the strip-like electron beam 7 uniformly incident on the space between the vertical scanning electrodes 8 and the mesh-like electrode 6 proceeds toward the fluorescent screen 5 by serially changing the voltage applied to each of the vertical scanning electrodes 8. Fig. 3 shows how the strip-like electron beam 7 goes toward the mesh-like electrode 6 by regulating the voltages applied to the vertical scanning electrodes 8A - 8E. First, let the ordinary electric potential of the vertical scanning electrodes 8 and the mesh-like electrode 6 be 200 V. Then, the electric potential of the vertical scanning electrodes 8A and 8B is set as that of a cathode 11, that is, 0 V, and that of the vertical scanning electrode 8C is set as an intermediate value 100 V. Thus, the strip-like electron beam 7 is deflected by the electric field indicated by dashed lines in this figure toward the mesh-like electrode 6. Next, it will be hereunder described how a method for performing the vertical scanning is effected by using the above described operation by referring to Figs. 4 (A) and (B). In Fig. 4 (B), reference numeral 31 indicates a period, in which a picture is effectively displayed, in one field (hereunder referred to as "1 V"). Further, the waveforms of the voltage signals applied to the vertical scanning electrodes 8A - 8Z are represented by reference characters 8AS - 8ZS, respectively. First, when the electric potential of the vertical scanning electrode 8A o is fixed to 0 V, and the potential of the electrodes 8A and 8B is set as 100 V and 200 V, respectively, the strip-like electron beam 7 is incident at a point a on the mesh-like electrode 6. Further, after a horizontal scanning period (hereunder referred to as "1 H") is elapsed, the potential of the vertical scanning electrodes 8A, 8B and 8C are set as 0 V, 100 V, and 200V, respectively, and then the strip-like electron beam 7 is incident at a point b on the mesh-like electrode 6. By serially changing the voltage applied to each of the vertical scanning electrodes 8C - 8Z similarly as in case of the vertical scanning electrodes 8A o - 8B above described, the position of incidence, at which the strip-like electron beam 7 is incident, on the mesh-like electrode 6 changes from the point a to that z , thereby performing the vertical scan. Incidentally, the voltage applied to the vertical scanning electrode 8Z o is constantly made equal to that applied to the mesh-like electrode 6. In this case, it is apparent that the interval between the adjacent positions of incidence on the mesh-like electrode 6 is equal to that between the contiguous vertical scanning electrodes 8. Further, in such an operation, the angles of incidence of the strip-like electron beam 7 to the points a - z on the mesh-like electrode 6 are equal to each other. Thus, are obtained the beams each having an even or constant width in the vertical direction. In order to perform an interlace scanning operation as an ordinary television system does, the voltages, which are 200V or 100 V in case of a first field, applied to the vertical scanning electrodes 8A, 8B, are set as values higher or lower than the values of the voltages applied thereto in case of the first field such that as to a second field, the electron beam 7 is incident on points which are placed between the positions of incidence thereof in case of the first field. Next, the electron beam 7 deflected toward the mesh-like electrode 6 passes through the openings in the mesh-like electrode 6 and is incident on the fluorescent screen 5. The video signal is supplied to each control electrode 2 under the fluorescent screen 5, and when the fluorescent material 3 is irradiated with the beam, is obtained the emission of light, of which the intensity corresponds to the voltage of the video signal and the time of supplying thereof. In the foregoing manner, by supplying the video signal of each "1 H" to each control electrode 2 and further effecting the vertical scanning of the strip-like electron beam 7, a desired picture is obtained. At that time, a partition 4 made of insulating material is provided between each control electrode 2 and the fluorescent material 3. Thereby, the withstand voltage between the adjacent control electrodes 2 can be considerably increased, and a light picture can be obtained. Next, a second embodiment of the present invention will be described hereinbelow by referring to Figs. 5 and 6. As is seen from Fig. 5 which shows the construction of the second embodiment of the present invention, the second embodiment is different from the first embodiment of Fig. 2 in that control electrodes 2 formed on an inner surface of a casing 1 are connected to buses 26, 27 and 28 every three control electrodes 2, that is, the control electrodes 2 are divided into three sets thereof, each set connected to a corresponding one of the buses 26, 27 and 28. In addition, the second embodiment is further different from the first embodiment in that in order to divide and emit the electron beam 7 to every three of the control electrodes 2, openings, of which the section is circular or rectangular, are bored in other control electrodes 23 and accelerating electrodes 24 provided just prior to a cathode 22, that the control electrodes 23 are divided in such a manner that each control electrode 23 corresponds to every three control electrodes 2 and that although back electrodes 21 and a vertical auxiliary deflecting electrode 10 are similarly provided in the first and second embodiments, in case of the second embodiment, horizontal deflecting electrodes 25 for deflecting each electron beam in the horizontal direction are provided between the vertical auxiliary deflecting electrode 10 and the accelerating electrode 24. In Fig. 5, reference numeral 29 indicates insulating films for preventing the short-circuiting of each bus 26, 27 and 28 and other control electrodes 2 than the control electrodes 2 to be connected to the bus 26, 27 and 28. Next, an operation of the second embodiment will be described hereinafter. First, the electron beam 7 generated by the cathode 22 is forced to proceed toward control electrodes 23 by the electric field applied to the back electrodes 21. Then, the electron beam 7, which is uniformly distributed in the horizontal direction, is divided in the horizontal direction by the control electrodes 23 divided in the horizontal direction. Further, the individual electron beam 7 is modulated by the corresponding control electrodes 23. The electron beam 7 passed through the corresponding control gate 23 further passes through the accelerating electrode 24 and the horizontal deflecting electrodes 25 which are divided and arranged in such a manner to let each electron beam pass between a corresponding pair thereof. Subsequently, the focusing of the electron beam 7 in the vertical direction and the correction of the position of the electron beam 7 are performed by the vertical auxiliary deflecting electrode 10. Thereafter, similarly as in case of the first embodiment, the electron beam 7 proceeds the space between the vertical scanning electrodes 8 and the control electrodes 2. Further, the electron beam 7 is serially deflected to the side of the control electrodes 2 and causes the fluorescent material 30 provided on the control electrodes 2 to emit light. At that time, the control electrodes 2 are divided into three groups by the buses 26, 27 and 28 as above described, and the voltage signal as shown in Fig. 5 is applied to these three groups of the control electrodes 2 through each bus 26, 27 and 28. That is, for a period of which the length is a third that of "1 H" (hereunder represented by the expression "(1/3)H"), a voltage EA required for causing the fluorescent material 30 to emit light is serially applied to each bus 26, 27 and 28. Here, let the fluorescent materials 30, which correspond to the control electrodes 2 connected to the buses 26, 27 and 28, correspond to, for example, R, G and B light sources, respectively. Further, for a first "(1/3)H" period, the R light source emits light; for a second "(1/3)H" period, the G light source; for a third "(1/3)H" light source, the B light source. Naturally, an electron beam corresponding to each of light sources respectively corresponding to the set of R, G and B is generated. By modulating the respective electron beams by serially applying R, G and B signals to the control electrodes 23 in synchronization with voltage pulses applied to the R, G and B light sources, color representation of a picture can be displayed on the screen of the display. Furthermore, each electron beam is deflected by the horizontal deflecting electrodes 25 to the respective groups of the control electrodes 2 connected to the buses 26, 27 and 28. By serially deflecting the electron beams to the R, G and B light sources or fluorescent materials 30 in synchronization with the voltage signals applied to the control electrodes 23, portions of the picture having red, green and blue colors are serially displayed on the screen. In the second embodiment, the divisor used for dividing the control electrodes 2, that is, the number of the groups of the control electrodes 2 is not necessarily 3 and may be multiples of 3. In the latter case, the adjacent electron beams are alternately generated every half of "1 H", that is, "(1/2)H". Thereby, can be prevented the deterioration in the horizontal resolution due to the overlap of the various electron beams resulted from the size of a horizontal spot diameter of the electron beam. Further, the control electrodes 2 are connected to the buses 26, 27 and 28 every two control electrodes 2. Moreover, as described above, the electron beam generated from the cathode 22 is modulated by the control electrodes 23 provided prior to the cathode 22. However, the same effects can be obtained by dividing the back electrodes 21 provided in the back surface of the cathode 22 into plural groups thereof in the horizontal direction, then applying modulation signals to the respective groups of these control electrodes and further modulating the electron beam generated from the cathode 22. Next, a third embodiment of the present invention will be described hereinafter by referring to Fig. 7 to Figs. 9 (A) and (B). Fig. 7 is a sectional view of the vertical scanning electrode portion for illustrating the condition of applying a voltage to each vertical scanning electrode 201, as well as the orbits of the electron beams 204. Fig. 8 is a graph for illustrating a model for obtaining the orbits of reflected electron beams 204 of Fig. 7. Further, Fig. 9 (A) is a perspective view of the display of Fig. 7 and Fig. 9 (B) is time chart for showing the waveforms and various timing of voltage signals applied to each vertical scanning electrode 201. Referring to Fig. 7, a voltage V D , which is equal to the voltage applied to the fluorescent screen 203, is applied to a vertical scanning electrode 201-1 at the side where the electron beam 204 proceeding straight on is incident. Further, another voltage (V D - V CC ) less than the voltage V D applied to the fluorescent screen 203 is applied to the subsequent vertical scanning electrode 201-2. Then, the electron beam 204 is subject to the deflection and focussing effected by an electrostatic lens formed between the vertical scanning electrodes 201-1 and 201-2 and is incident at a point P on the fluorescent screen 203. This position of incidence of the electron beam 204 is determined on the basis of the voltage (V D - V CC ) applied to the vertical scanning electrode 201-2 and an interval d between each vertical scanning electrode 201 and the fluorescent screen 203. A part of the electron beam 204 incident at the point P on the fluorescent screen 203 is reflected, and in addition the magnitude of the angle  1 of reflection of the elecron beam 204 is nearly equal to that of the angle  2 of incidence thereof. Moreover, an initial speed of the reflected electron is almost equal to the speed of the electron incident on the fluorescent screen 203. The orbit of the reflected electron, in case where the voltage (V D - V CC ) is further applied to another vertical scanning electrode 201-3, is determined by modelling it as shown in Fig. 8. The electrode 205 corresponds to the vertical scanning electrode 201, and the voltage (V D - V CC ) is also applied thereto. Further, the electrode 206 corresponds to the fluorescent screen 203 and thus the voltage V D is applied thereto. Here, a given point on the electrode 206 is taken as an origin, and it is assumed that an electron beam 204 is emitted from the origin at an angle  of emission and at an initial speed v O . Then, the abscissa x and the ordinate y of the electron is given by using a parameter representing time as follows. x = V O sin  · t y = -(e/2m)Et 2 + v O cos  · t (E = - V CC / d) Further, by eliminating t from the equations (1) and assuming that the initial speed v O corresponds to the voltage V D , that is, V O = 2eV D /m where "e" denotes the electric charge of an electron and "m" denotes the mass of the electron. Thus, an equation giving the orbit of the electron is obtained as follows. y = -{Ex 2 / (4V D sin 2 )} + (x / tan  ) From this equation, the maximum value ym of the ordinate y and the value xm of the corresponding abscissa x are obtained as follows. xm = 2V D sin  cos  / E ym = V D cos 2  / E For example, in case where V D = V CC = 100 V, d = 10 mm, the initial speed of the electron beam 204 from the cathode (not shown) v O = 0, the angle of incidence of the electron beam at the point P on the fluorescent screen 203 is obtained as almost 42 ° (degrees). Further, in such a case, if the angle of incidence is assumed not to be 42 ° (degrees) but to be 45 ° (degrees), the values of xm and ym of the orbit of the electron are obtained as follows. xm = 10 mm, ym = 5 mm Provided that at least the electric potential on the vertical scanning electrodes 201-3 including and subsequent to the electrode 201F at the position of the reflected electron closest to the vertical scanning electrode 201 (that is, the position farthest from the point P) is equal to the potential V D on the fluorescent screen 203, it is understood from the foregoing consideration that the electron beam 204 proceeds as indicated by a dashed curve shown in Fig. 7 and is never incident on the fluorescent screen 203. Further, if the voltage (V D + V M ) higher than the voltage V D on the fluorescent screen 203 is applied to the vertical scanning electrode 201-3, the re-incidence of the electron beam 204 can be more surely prevented. Next, Fig. 9 shows the practical timing of applying the voltage to each vertical scanning electrode 301 in case of a standard television system. In Fig. 9 (B), time charts (b) - (z) are used to represent the timing of applying voltages to vertical scanning electrodes 301-A, 301-B, ..., 301-Z, respectively. In Fig. 9 (A) , an electron beam 303 generated from an electron source 307 passes through grid electrodes 306 and 305 and a shielding electrode 304 and further proceeds the space between vacuum casings 308 and 309. Then, as described above, the electron beam 303 is serially deflected by the voltage applied to the vertical scanning electrodes 301 [301A - 301Z] to the fluorescent material 302 so as to let the fluorescent material 302 emit light to display a picture. At that time, the voltage signal, of which the waveform is shown in Fig. 9 (B), is applied to the vertical scanning electrode 301 [301A - 301Z]. In Fig. 9 (B), reference numeral 310 of Fig. 9 (B) (a) indicates a vertical synchronization signal. First, for a period of "1 H" posterior to the initiation of the vertical scan, the voltage (V D - V CC ) is applied to the vertical scanning electrode 301-A. Further, the voltage V D is applied to other vertical scanning electrodes 301-B - 301-Z. Additionally, after the lapse of a period of time required for the vertical scanning of a distance at least two times the distance of xm obtained in the foregoing consideration determined on the basis of the driving condition and the distance d between the vertical scanning electrode 301 and the fluorescent screen 302, the voltage V D higher or equal to the potential on the fluorescent screen 302 is applied to the vertical scanning electrode 301-A. By setting the period of applying the voltage (V D - V CC ) to the electrode 301-A as the time "1 H" multiplied by an integer a (hereunder represented by the expression " a H"), the circuits can be easily designed. After the lapse of the period "1 H", the voltage applied to the vertical scanning electrode 301-B changes from V D to (V D - V CC ), and further after the application of the voltage (V D - V CC ) to the vertical scanning electrode 301-B for a period of " a H", the voltage applied to the electrode 301-B is changed into V D . Since then, similarly as in case of the foregoing cases, the voltage (V D -V CC ) lower than the potential on the fluorescent screen 302 is maintained for a period of " a H", and further a voltage signal of which the phase is shifted by an amount corresponding to the period "1 H" is applied to each vertical scanning electrode 301, thereby performing the vertical scanning operation. As above stated, an electron beam generated from a strip-like cathode extending in the horizontal direction is serially deflected by scanning electrodes to mesh-like electrodes and a light emitting portion in which control electrodes divided in the horizontal direction at a predetermined pitch and fluorescent material are arranged. The light emitting portion is used to display a picture by applying modulation signals to the respective control electrodes, or by connecting each color light source to a common bus and then applying a sequential voltage pulse signals to each color light source and further letting the fluorescent material emit light by using modulated electron beams. The light emitting portion is divided correspondingly to kinds of colors, and then the emission of light of each color is effected by the corresponding divided portions independent from each other. Thereby, color mixture can be avoided. Furthermore, in the display of the present invention, the electron beam is generated uniformly in the horizontal direction. Alternatively, a plurality of the electron beams are simultaneously generated. Thus, the electron beam can be highly efficiently used. Therefore, a picture having high luminance can be displayed. Moreover, partitions are provided in a divided portion of control electrodes of the display according to the present invention. Thereby, the withstand voltage can be increased and thus a high voltage can be applied to the control electrodes, whereby light having high luminance can be emitted. Incidentally, by the method for driving the display of the present invention, a ghost image due to a reflected electron beam and a secondary electron beam can be cancelled, thereby increasing picture quality.

Claims: A flat panel type display having a screen, control electrodes (2) divided in a first direction of said screen and provided in a vacuum casing (1), a light emitting portion (5) composed of fluorescent materials (3) provided on said control electrodes (2), a mesh-like electrode (6) provided in said casing (1) and facing said fluorescent materials (3), scanning electrodes (8) each divided in a second direction perpendicular to the first direction of said screen and facing said mesh-like electrode (6), and an electron source (9) provided on the extension of the space between said light emitting portion (5) and said scanning electrodes (8) for generating electron beams uniformly or discretely in the first direction of said screen, said flat panel type display being characterized in that a partition (4) made of insulating material is provided between each pair of adjacent divided portions of said control electrode (2). The flat panel type display as set forth in claim 1, characterized in that said electron source (9) modulates each electron beam independently from other beams and is provided with a deflecting electrode (10) for deflecting the electron beams to a predetermined position on said light emitting portion (5). The flat panel type display as set forth in claim 1, characterized in that each of said control electrodes (2) receives a modulation signal from an external circuit of the display, and when said fluorescent material (3) is irradiated with an electron beam, the intensity of light emitted therefrom corresponds to the voltage of the modulation signal. The flat panel type display as set forth in claim 1, wherein each group of n (n is an integer to or greater than 2) of said control electrodes (2) are electrically connected to a common bus (26, 27, 28) to which a voltage pulse is applied from an external circuit, and the phase of a voltage pulse applied to each common bus is shifted from the phase of another voltage pulse applied to another common bus (26, 27, 28) adjacent thereto. The flat panel type display as set forth in claim 1, characterized in that said scanning electrodes (8) are activated in response to voltage pulses supplied from an external circuit thereto from one of said scanning electrodes (8) positioned at an end in the second direction to another of said scanning electrodes (8) positioned at the other end in the second direction, respectively, so as to serially deflect the electron beam to said light emitting portion (5).

Inventors: KAWAUCHI YOSHIKAZU, MIYAMA HIROSHI, NISHIDA JUN, TOMII KAORU, KAWAUCHI, YOSHIKAZU, MIYAMA, HIROSHI, NISHIDA, JUN, TOMII, KAORU
Applicants: MATSUSHITA ELECTRIC IND CO LTD, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD.
Application year: 1989
Main classification: H01J31
IPC codes: H01J31, G09G1