JPH07177446A - Image display device - Google Patents

Abstract

PURPOSE:To suppress the increase of the power consumption of a driving circuit and to reduce the degradation of picture quality by timewisely changing the pulse height value of control signals to be outputted highly in a low luminance time area while being synchronized with modulation control signals in a pulse width modulation circuit for outputting signals to be impressed to a beam current controlled electrode. CONSTITUTION:The pulse height value of trailing edge fixed output control signals from PWM circuits 37a-37n is timewisely changed highly in the low luminance time area in synchronism with the control signals. The ratio of the time area for which the spot shape of the area is in an abnormal state decreases as a pulse width is narrowed compared to a conventional case and thus, the picture quality of low luminance is improved. Also, compared to the case of simply raising the pulse height value of the output control signals from the PWM circuits 37a-37n over the entire time areas, the power consumption of the circuit is suppressed and the improvement degree of the picture quality degraded in the low luminance is approximately equal. Even in the case where the output control signals from the PWM circuits are leading edge fixed and pulse.width modulated, by timewisely changing the pulse height value of the control signals highly in the low luminnnce time area on a leading edge side, a similar effect is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generates an electron beam for each section when a screen image projected on a screen plate is divided into a plurality of sections in the vertical direction, and each electron beam is generated for each section. The present invention relates to an image display device that deflects a beam in a vertical direction to display a plurality of lines and displays an image as a whole.

[0002]

2. Description of the Related Art In recent years, various flattening devices for displaying television images have been proposed.

An image display device as a flat-type color picture tube of this type has hitherto been disclosed in, for example, Japanese Patent Application Laid-Open No. 57-135590.
It has a structure as shown in the publication. The configuration will be described below with reference to the drawings.

As shown in FIG. 4, this image display device has a back electrode 1, a line cathode 2 as an electron beam emission source, a beam extraction electrode 3, and a beam flow control in this order from the rear to the anode side. An electrode 4, a focusing electrode 5, a horizontal deflection electrode 6, a vertical deflection electrode 7, a screen plate 8 and the like are arranged and configured, and these are housed inside a vacuum container.

The operation of the flat type image display device constructed as described above will be described below. As shown in FIG. 4, the line cathode 2 as an electron beam emission source is stretched in the horizontal direction so as to generate an electron beam that is distributed horizontally in a line, and the line cathode 2 is further vertical. A plurality of lines (only 7 lines 2a to 2g are shown in FIG. 4) are provided at regular intervals in the direction. In this configuration, the line cathodes are spaced at 4.4 mm and the number of line cathodes is 19, and the line cathodes are 2 to 2 in number. The distance between the line cathodes cannot be freely set to a large value, and the vertical deflection electrode 7 and the screen plate 8 which will be described later will be used.
It is regulated by the interval. As the structure of these wire cathodes 2, an oxide cathode material is applied to the surface of a tungsten rod having a diameter of 10 to 30 μm. As will be described later, the line cathode is controlled so as to sequentially emit an electron beam from the upper line cathode 2a to the lower two cathodes at regular intervals.

The back electrode 1 suppresses the generation of electron beams from the line cathodes other than the corresponding line cathode, and at the same time, the electron beam is emitted.
It also has the function of pushing the mud only in the anodic direction. Figure 4
Although a vacuum container is not shown, it is possible to use the back electrode 1 to form a structure integrated with the vacuum container. Bee
The lead-out electrode 3 is a conductive plate 11 having a plurality of through-holes 10 arranged in a row at regular intervals in the horizontal direction facing each of the line cathodes 2a to 2 and an electron beam emitted from the line cathode 2. Through the through hole 10.

Next, the beam flow control electrode 4 is connected to the line cathodes 2a to 2b.
A plurality of vertically long conductive plates 15 each having a through hole 14 at a position facing each other are arranged side by side in a horizontal direction at a predetermined interval. 11 in this configuration
Four beam flow control electrode conductive plates 15a to 15n are provided (only eight are shown in FIG. 4). The beam flow control electrode 4 synchronizes the passing amount of each electron beam horizontally divided by the beam extraction electrode 3 with the picture element of the video signal and in synchronization with the horizontal deflection timing described later. Let me control.

The focusing electrode 5 is a conductive plate 17 having a through hole 16 at a position facing each through hole 14 provided in the beam flow control electrode 4, and focuses the electron beam.

The horizontal deflection electrode 6 is composed of a plurality of conductive plates 18 and 18 'vertically arranged along both sides of the through hole 16 in the horizontal direction. Voltage is applied. The electron beam for each picture element is deflected in the horizontal direction, and the R, G, and B phosphors are sequentially irradiated on the screen plate 8 to emit light. In this configuration, each electron beam is deflected by 2 trio.

The vertical deflection electrode 7 is composed of a plurality of conductive plates 19 and 19 'arranged in the horizontal direction at the respective intermediate positions in the vertical direction of the through hole 16, and a voltage for vertical deflection is applied to the vertical deflection electrode 7 to generate an electronic beam. -The beam is deflected vertically. In this structure, the electron beam generated from one line cathode is vertically deflected by 12 lines by the pair of electrodes 19 and 19 '. The vertical deflection electrodes 7 composed of 20 pieces form 19 pairs of vertical deflection conductors corresponding to the 19 line cathodes, respectively, and 228 pieces of the vertical deflection conductors 228 are arranged on the surface of the screen plate 8 in the vertical direction. Drawing a horizontal scan line.

As described above, in this structure, a plurality of horizontal deflection electrodes 6 and vertical deflection electrodes 7 are arranged in a comb shape. Furthermore, by setting the distance to the screen plate 8 longer than the distance between the horizontal and vertical deflection electrodes, the electron beam can be moved with a small deflection amount.
It becomes possible to irradiate on the surface of. This makes it possible to reduce deflection distortion both horizontally and vertically.

As shown in FIG. 4, the screen plate 8 is formed by coating the back surface of the glass plate 21 with the phosphor 20 in a stripe shape. Although not shown, metal back and carbon are also applied. The phosphor 20 deflects the electron beam passing through one through hole 14 of the beam flow control electrode 4 in the horizontal direction so as to irradiate the phosphor pairs of three colors R, G and B for two trio. It is provided and is applied in stripes in the vertical direction. In FIG. 4, the screen
The broken lines on the panel 8 indicate vertical divisions displayed corresponding to the plurality of line cathodes 2, and the two-dot chain line is displayed corresponding to each of the plurality of beam flow control electrodes 4. Indicates the horizontal division. As shown in the enlarged view of FIG. 5, one section partitioned by a broken line and a two-dot chain line has two trio R, G, and B phosphors in the horizontal direction and a width of 12 lines in the vertical direction. ing. In this example, the size of one section is 1 mm in the horizontal direction and 4.4 mm in the vertical direction.

Although the phosphors of three colors R, G and B are shown in a stripe shape in FIG. 5, they may be arranged in a delta shape. However, when they are arranged in a delta shape, it is necessary to apply horizontal deflection and vertical deflection waveform voltages suitable for them. Note that in FIG. 5, the vertical and horizontal dimensional ratios are different from the actual image displayed on the screen for convenience of explanation.

Further, in this configuration, one of the beam flow control electrodes 4 is
Two R, G, and B phosphors are provided for one through hole 14, but one trio or three or more trio may be used. However, the beam flow control electrode 4
In this case, R, G, B video signals of 1 trio or 3 trios or more are sequentially added, and horizontal deflection must be performed in synchronization with them.

Next, the operation of the drive circuit for driving the image display device will be described with reference to FIG.

First, the drive portion for irradiating the screen 8 with the electron beam and displaying the same will be described. The power supply circuit 22 is a circuit for applying a predetermined bias voltage to each electrode of the image display device. The back electrode 1 has V1, the beam extraction electrode 3 has V3, the focusing electrode 5 has V5, and the screen plate. V8 for 8
Apply the DC voltage of.

The pulse generating circuit 39 uses the vertical synchronizing signal V and the horizontal synchronizing signal H to create a line cathode drive pulse.
FIG. 7 shows an example of the timing.

The line cathode drive circuit 26 receives the line cathode drive pulse and heats the line cathode 2 while the drive pulse is at a high potential. At this time, the heated line cathode is applied to the line cathode 2 more than the potential around the line cathode 2 determined by the bias voltage applied to the back electrode 1 and the beam extraction electrode 3. Since the potential is higher,
No electrons are emitted from the line cathode.

On the other hand, the line cathode 2 emits electrons while the driving pulse is at a low potential. At this time, the potential of the line cathode 2 applied to the line cathode 2 is higher than the potential around the line cathode 2 determined by the bias voltage applied to the back electrode 1 and the beam extraction electrode 3. Since it becomes low, electrons are emitted from the line cathode 2.

As is apparent from the above description, electrons are emitted from the 19 line cathodes 2a to 2t only during the 12 horizontal scanning periods in which low potential driving pulses (a tot) are applied. In order to form one screen, it is sufficient to sequentially switch the potentials from the upper line cathode 2a to the lower line cathode 2 by 12 scanning periods.

Next, the deflection portion will be described. As shown in FIG. 6, the deflection voltage generating circuit 40 includes a direct memory access controller (hereinafter referred to as a DMA controller).
41, a deflection voltage waveform storage memory (hereinafter referred to as deflection memory) 42, a horizontal deflection signal generator 43h, a vertical deflection signal generator 43v, and the like.
v'and horizontal deflection signals h, h '. In this configuration, the vertical deflection signal is displayed in one field for 228 horizontal scanning periods in consideration of overscan. Further, the memory address area storing the vertical deflection position information corresponding to each line is divided into a first field and a second field, and each set has a memory capacity. When displaying, data is read from the corresponding deflection memory 42, converted into an analog signal by the vertical deflection signal generator 43v, and added to the vertical deflection electrode 7.

The vertical deflection position information stored in the deflection memory 42 is composed of substantially regular data every 12 horizontal scanning periods, and the waveform converted into the deflection signal is also approximately 1.
Although it is a two-stage vertical deflection signal, it has a memory capacity of two fields as described above so that the position can be finely adjusted for each horizontal scanning line.

Further, with respect to the horizontal deflection signal, it is necessary to horizontally deflect the electron beam in six steps in one horizontal scanning period and a memory is provided so that the deflection position can be finely adjusted for each horizontal scanning. . Therefore, to display 456 horizontal scanning periods in one frame, a memory of 456 × 6 = 2736 bytes is required, but since the data of the first field and the second field are shared. In fact, it uses 1368 bytes of memory. At the time of display, the deflection information corresponding to each horizontal scanning line is read from the deflection memory 42, converted into an analog signal by the horizontal deflection signal generator 43h, and added to the horizontal deflection electrode 6.

To summarize the above, during the display period excluding the vertical blanking period of the vertical period, the low-potential drive pulse of the linear cathodes 2a to 2 is emitted from the linear cathode. The electron beam is divided into 114 sections in the horizontal direction by the beam extraction electrode 3 to form 114 electron beam rows. As will be described later, this electron beam is controlled by the beam flow control electrode 4 for each section so that the amount of the beam passes, and after being focused by the focusing electrode 5, it has approximately 6 stages as shown in FIG. The horizontal deflection electrodes 18, 18 'to which a pair of changing horizontal deflection signals h, h' are applied are used to generate R1, G of the screen plate 8 in each horizontal display period.
1, B1 and R2, G2, B2 and other phosphors sequentially,
The horizontal display period / 6 is emitted at a time.

Thus, the raster of each horizontal line is 11
Displaying a color image on the surface of the screen plate 8 by modulating an electron beam for each of the four sections with a video signal corresponding to R1, G1, B1 and R2, G2, B2. You can

Next, the modulation control portion of the electronic beam will be described. First, in FIG. 6, signal input terminals 23R, 2
The R, G, and B video signals added to 3G and 23B are
It is added to 114 sets of sample-hold circuit sets 31a to 31n. Each of the sample-hold groups 31a to 31n is for R1, G1, B1, and R2, G2,
It is composed of six sample-hold circuits for B2.

The sampling pulse generating circuit 34 has a horizontal display period (about 50) of the horizontal period (63.5 μsec).
μsec), the 114 sets of sample-hold circuits 31
Each of a to 31n for R1, G1, B1, and R2
(114.times.6) sampling pulses Ra1 corresponding to the sample-hold circuits for G2, G2, and B2
Rn2 is sequentially generated. Each of the 684 sampling pulses includes 114 sample-hold circuit sets 31.
6 pieces are added to each of a to 31n, so that R1, G1, B1, R2 for each two picture elements when one line is divided into 114 pieces in each sample hold circuit set.
The video signals of G2 and B2 are individually sampled and
Be killed. 114 sets of R1 sampled,
The video signals of G1, B1, R2, G2, and B2 are 114 sets of memories 32a through after the end of the sample hold for one line.
32n are transferred all at once by the transfer pulse t, and are held here for the next one horizontal scanning period. The retained signal is 11
It is added to the four switching circuits 35a to 35n.

The switching circuits 35a to 35n are each composed of a circuit having individual input terminals of R1, G1, B1, R2, G2 and B2 and a common output terminal for sequentially switching and outputting them, and a switching pulse Switching pulse r applied from the generation circuit 36
Switching control is performed simultaneously by 1, g1, b1, r2, g2, and b2. The switching pulses r1, g1,
b1, r2, g2, and b2 divide each horizontal display period into six, and each horizontal display period / 6 switching circuit 35a-3.
5n are switched and the respective video signals of R1, G1, B1, R2, G2, and B2 are time-divided and sequentially output, and supplied to the pulse width modulation circuits 37a to 37n. Each switching circuit 3
The outputs of 5a to 35n are added to 114 sets of pulse width modulation circuits (hereinafter referred to as PWM circuits) 37a to 37n,
The pulse width is modulated according to the magnitude of each video signal of R1, G1, B1, R2, G2, and B2, and output. This PWM
The outputs of the circuits 37a to 37n serve as a control signal for modulating the electron beam, and are supplied to the beam flow control electrodes 4 of the display element 11.
It is added individually to the four conductive plates 15a to 15n.

Before and after the beam flow control electrode 4, a beam extraction electrode 3 to which a direct current voltage is normally applied and a focusing electrode 5 are close to each other, and 114 conductive plates 15a to 15n are provided.
PWM circuits 37a to 37n for outputting pulse control signals to the
In terms of alternating current, the load of can be represented by an equivalent circuit as shown in FIG. Here, 51a to 51
n is PWM from the electrostatic leak generated inside the vacuum container.
Resistors 53a to 53n inserted in the output stage for the purpose of protecting the circuit are capacitance components.

Output parts of the PWM circuits 37a to 37n (see FIG. 8).
The signal waveform at point A in (a) is shown in FIG. 8 (b), and the beam flow control electrode conductive plates 15a to 15n (B in FIG. 8 (a)) are actually shown.
The signal waveform applied to the point) is shown in FIG. Where T
Is the maximum pulse width, and dt is a unit for changing the pulse width. The pulse width is fixed in the trailing edge direction and changes in the dt unit up to the maximum T according to the video signal. Actually, this output waveform has resistors 51a to 51n and capacitance components 53a to 5n.
It is integrated by 3n and becomes a waveform, and is applied to the beam flow control electrode conductive plates 37a to 37n.

Next, the timing of horizontal deflection and display will be described. Switching of video signals of R1, G1, B1, R2, G2 and B2 in the switching circuits 35a to 35n, and electronic beam R by the horizontal deflection signal generator 43h.
The synchronization control is performed so that the switching timing and the order of horizontal deflection of the phosphors of 1, G1, B1, R2, G2, and B2 to the phosphors completely match. As a result, when the R1 phosphor is irradiated with the electron beam, the irradiation amount of the electron beam is controlled by the R1 control signal, and G1, B1, R
2, G2, and B2 are controlled in the same manner, and the emission of each phosphor of R1, G1, B1, R2, G2, and B2 of each picture element is changed to that of R1, G1, B1, R2, G2, and B2 of that picture element. Each picture element is controlled by the video signal, and each picture element is luminescently displayed according to the input video signal. This control is simultaneously executed for 114 sets (two picture elements each) for one line, an image of 228 picture elements for one line is displayed, and one field 228 lines are sequentially performed from the upper line. Then, an image is displayed on the surface of the screen plate 8. Further, the above-described operations are repeated for each field of the input video signal, and the television signal or the like is displayed on the screen plate 8.

The basic clock required for this configuration is shown in FIG.
Is supplied from the pulse generation circuit 39 shown in FIG. 1 and the timing is controlled by the horizontal synchronizing signal H and the vertical synchronizing signal V.

[0033]

However, in the above-mentioned conventional image display device, since a waveform accent occurs at the rising and falling edges of the pulse width modulated control signal applied to the beam flow control electrode of the display element, There is a time domain where a low voltage is applied, which is unfavorable for the spot shape of the electron beam, and the pulse width becomes narrower especially as the brightness becomes lower. There was a problem that the image quality at the time deteriorates.

The present invention solves the above-mentioned conventional problems. In consideration of the power consumption of the driving circuit, the deterioration of the image quality due to the abnormal spot shape at the time of low luminance is reduced and a good image is obtained. It is an object of the present invention to provide a driving means of an image display device capable of performing the above.

[0035]

In order to achieve this object, the image display device of the present invention is a PWM circuit which outputs a signal to be applied to a beam flow control electrode, and which is pulse width modulated. A driving unit is used that changes the crest value of the control signal to a high time in the low luminance time region in synchronization with the modulation control signal.

[0036]

By this driving means, the rising characteristic of the pulse-width-modulated control signal applied to the beam flow control electrode is improved, and the time region for applying a low voltage unfavorable to the spot shape of the electron beam is shortened. It is possible to realize an image display device in which an increase in power consumption of a drive circuit is suppressed to a small level and deterioration of image quality due to an abnormal spot shape at low luminance is suppressed.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a characteristic example showing the relationship between the voltage of the beam flow control electrode 4 of the image display apparatus according to the present embodiment and the vertical spot diameter of the electron beam with which the screen is irradiated, and FIG. ) Is a characteristic example showing the relationship between the voltage of the beam flow control electrode 4 and the beam current with which the screen is irradiated.

In the figure, region (a) is a region where the spot shape of the electron beam is normal, and the vertical spot diameter becomes smaller as the voltage of the beam flow control electrode becomes lower, and further the aperture is most narrowed. However, in this area, the horizontal spot diameter is slightly larger and smaller, and thus the state in which the vertical spot diameter is most narrowed is not the optimum state. The area (b) is an area where the spot shape of the electron beam is abnormal and causes deterioration of image quality. Area (c) is an area where the electron beam is cut off, and the screen is not illuminated.

FIG. 2A shows the PWM circuit 3 according to this embodiment.
Examples of output waveforms from 7a to 37n (point A in FIG. 8A), FIG. 2B shows conductive plates 15a to 15n for beam flow control electrodes (point B in FIG. 8B) according to this embodiment. 2C shows an example of an application control signal to the conventional PWM circuits 37a to 37.
An example of the output waveform from n, FIG. 2D is an example of the application control signal to the conventional conductive plates 15a to 15n for beam flow control electrodes.

As shown in the figure, in this embodiment,
The crest value of the output control signal of the trailing edge fixed from the PWM circuits 37a to 37n is changed over time to a low luminance time region in synchronization with the control signal.

According to this embodiment using the driving means as described above, the ratio of the time region in which the spot shape in the above-mentioned region (b) is abnormal decreases as the pulse width becomes narrower than in the conventional case. Therefore, the image quality of low brightness can be improved. Further, the PWM circuits 37a to 37n are simply used.
The power consumption of the circuit can be suppressed, and the degree of improvement in image quality that deteriorates at low luminance is almost equal to that in the case where the peak value of the output control signal from is increased over the entire time region.

Even when the output control signal from the PWM circuit is pulse width modulated with the leading edge fixed, the same effect can be obtained by changing the crest value of the control signal to a high value in the low luminance time region on the leading edge side. It is clear that

(Embodiment 2) When the first invention is carried out, the conductive plate 15 for the beam flow control electrode is provided at a low brightness.
The applied voltage to a to 15n becomes high, and the vertical spot diameter of the electron beam becomes large. In the case where this itself becomes a problem, one embodiment of the second invention for improving this will be described with reference to the drawings.

FIG. 3A is a circuit configuration diagram of the output part of the PWM circuit for driving the beam flow control electrode of this embodiment.
From the output parts of the PWM circuits 37a to 37n to the 114 conductive plates 15a to 15n of the beam flow control electrodes, resistors 51a to 51n are connected in series and the constant voltage diode 52 is connected in parallel.
a to 52n are arranged.

FIG. 3B shows the PWM circuit 3 according to this embodiment.
Examples of output waveforms from 7a to 37n (point A in FIG. 3A), FIG. 3C shows conductive plates 15a to 15n for beam flow control electrodes (point B in FIG. 3A) according to this embodiment. It is an example of the application control signal to.

As shown in the figure, also in this embodiment, as in the first embodiment of the invention, the PWM circuits 37a to 37a are provided.
The crest value of the output control signal fixed at the trailing edge from n is changed to a high time in the low brightness time region in synchronization with the control signal, but the voltage applied to the conductive plates 15a to 15n for the beam flow control electrodes is appropriate. Voltage diode 52a set to various values
Clipped by ~ 52n.

According to the present embodiment using the driving means as described above, it is possible to improve the image quality of low luminance and to use it for the beam flow control electrode at low luminance, as in the first embodiment of the invention. Since the applied voltage to the conductive plates 15a to 15n can be set to an appropriate value, the vertical spot diameter of the electron beam can be set.

[0049]

As described above, according to the first aspect of the present invention, the PW which outputs the signal applied to the beam flow control electrode is output.
In the M circuit, by using a driving means for changing the crest value of the output pulse-width modulated control signal to a low luminance time region in synchronization with the modulation control signal, the power consumption of the driving circuit is increased. (EN) An image display device in which the rise characteristics of a pulse-width-modulated control signal applied to a beam flow control electrode are improved while suppressing the increase in image quality, and the deterioration of image quality due to an abnormal spot shape at low brightness is reduced. You can

According to the second aspect of the present invention, the effect of the first aspect is maintained by the circuit configuration in which the constant voltage diode is arranged in parallel with the resistor in series from the output section of the PWM circuit to the beam flow control electrode. In the above, it is possible to provide an image display device in which the voltage applied to the beam flow control electrode can be set to an appropriate value at low brightness and the vertical spot diameter of the electron beam can be set.

[Brief description of drawings]

1A is a diagram showing a relationship between a beam flow control electrode voltage of an image display device and a vertical spot diameter of an electron beam; FIG. 1B is a view showing a relationship between a beam flow control electrode voltage of the image display device and a beam current to a screen. Figure shown

FIG. 2A is a diagram of an output waveform from a PWM circuit in the embodiment of the first invention. FIG. 2B is a diagram of a waveform applied to a conductive plate for a beam flow control electrode in the embodiment of the first invention. Figure of the output waveform from the conventional PWM circuit (d) Figure of the waveform applied to the conductive plate for the conventional beam flow control electrode

FIG. 3A is a circuit configuration diagram of an output section of a PWM circuit according to an embodiment of the second invention. FIG. 3B is a diagram of output waveforms from the PWM circuit according to the embodiment of the second invention. Of Waveform Applied to Conductive Plate for Beam Flow Control Electrode in Example

FIG. 4 is an exploded perspective view of an image display device used in the present invention.

FIG. 5 is an enlarged view of a phosphor screen of an image display device used in the present invention.

FIG. 6 is a block diagram of a drive circuit of an image display device used in the present invention.

FIG. 7 is a waveform diagram for explaining the operation of the image display device used in the present invention.

8A is a circuit configuration diagram of an output section of a PWM circuit used in the present invention and an equivalent circuit diagram of an electrode to be driven. FIG. 8B is a diagram of an output waveform from a conventional PWM circuit. FIG. 8C is a conventional beam flow control. Figure of applied waveform to conductive plate for electrode

[Explanation of symbols]

 3 beam extraction electrode 5 focusing electrode 15a to 15n conductive plate for beam flow control electrode 37a to 37n PWM circuit 51a to 51n resistor 52a to 52n constant voltage diode 53a to 53n capacitance component

Claims (2)

[Claims] 1. A plurality of line cathodes for generating an electron beam,
A plurality of beam flow control electrodes for controlling the electron beam emitted from the linear cathode, electrodes for deflecting the electron beam, a screen plate coated with a phosphor that emits light when irradiated with the electron beam, and a video signal A drive circuit for applying a control signal modulated according to the above to the beam flow control electrode,
An image display device characterized in that, in the drive circuit, its crest value is changed over time in a low brightness time region in synchronization with the control signal. 2. A constant voltage diode is arranged in parallel with a resistor in series from the output section of the drive circuit to the beam flow control electrode to limit the peak value applied to the beam flow control electrode. The image display device according to claim 1.