JPH0329351B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention generates an electron beam for each division when a screen on a screen is vertically divided into a plurality of divisions, and generates an electron beam for each division. The present invention relates to an apparatus for displaying a plurality of lines by vertically deflecting a beam to display a television image as a whole.

Conventional configurations and their problems Traditionally, cathode ray tubes have been mainly used as display elements for displaying color television images, but conventional cathode ray tubes are extremely long and thin compared to the screen size. It would have been impossible to create a television receiver. In addition, EL display elements, plasma display devices, liquid crystal display elements, etc. have recently been developed as flat display elements.
All of them are insufficient in terms of performance such as brightness, contrast, and color display, and have not yet been put into practical use.

Therefore, with the aim of achieving a flat display device using electron beams, when the screen on the screen is vertically divided into multiple sections, an electron beam is generated for each section, and each section is A device was invented that displayed a plurality of lines by vertically deflecting an electron beam to display a television image as a whole.

First, a basic configuration of the image display element used here will be explained with reference to FIG. This display element includes, in order from the back to the front, a back electrode 1,
Line cathode 2 as a beam source, vertical focusing electrode 3,
3', a vertical deflection electrode 4, a beam flow control electrode 5, a horizontal focusing electrode 6, a horizontal deflection electrode 7, a beam acceleration electrode 8, and a screen 9. ) is housed inside a vacuum chamber. A line cathode 2 serving as a beam source is stretched horizontally so as to generate an electron beam distributed linearly in the horizontal direction. Only four (2a to 2d are shown) are provided. In this example, it is assumed that 15 are provided. Let them be 2a to 2o.
These wire cathodes 2 are constructed by coating the surface of a tungsten wire with a diameter of 10 to 20 μΦ with an oxide cathode material for thermionic emission. These line cathodes 2a to 2o are heated so as to generate a thermionic electron beam when a current is passed through them.
As will be described later, the electron beams are controlled to be emitted sequentially from the line cathode 2a for a fixed period of time. The back electrode 1 suppresses generation of electron beams from line cathodes other than the line cathode controlled to emit electron beams for a certain period of time, and pushes out the generated electron beams only in the forward direction. act. The back electrode 1 may be formed by a coating of a conductive material applied to the inner surface of the rear wall of the glass bulb. Further, instead of the back electrode 1 and the linear cathode 2, a planar electron beam emitting cathode may be used.

The vertical focusing electrode 3 is a conductive plate 11 having a horizontally long slit 10 facing each of the line cathodes 2a to 2o. Focus. An electron beam for one horizontal line (360 pixels) is extracted at the same time. In the figure, only one section in the horizontal direction is shown. The slit 10 may be provided with crosspieces at appropriate intervals in the middle, or may be substantially configured as a slit by a row of many through holes arranged horizontally at small intervals (nearly touching intervals). may be done. Vertical focusing electrode 3'
is also similar.

A plurality of vertical deflection electrodes 4 are arranged horizontally in the middle of each of the slits 10, and are each composed of conductors 13 and 13' provided on the upper and lower surfaces of an insulating substrate 12. has been done. And the opposing conductors 13, 13'
A vertical deflection voltage is applied between them to deflect the electron beam in the vertical direction. In this example, the electron beam from one line cathode 2 is vertically deflected to 16 line positions by a pair of conductors 13, 13'. The 16 vertical deflection electrodes 4 constitute 15 pairs of conductors corresponding to each of the 15 line cathodes 2, and in the end, the electron beams are emitted so as to draw 240 horizontal lines on the screen 9. deflect.

Next, the control electrodes 5 are composed of conductive plates 15 each having a vertically long slit 14, and a plurality of control electrodes 5 are arranged in parallel in the horizontal direction at a predetermined interval. In this example, 180 control electrode conductive plates 1
5-1 to 15-n are provided. (9 in the diagram)
(only books shown). Each of the control electrodes 5 separates and extracts the electron beam into two picture elements in the horizontal direction, and controls the amount of electron beam passing therethrough in accordance with a video signal for displaying each picture element. Therefore, the conductive plates 15-1 to 15-n for the control electrode 5 are
If 180 lines are provided, 360 pixels can be displayed per horizontal line. In addition, in order to display images in color, each picture element is displayed with phosphors of three colors R, G, and B, and each control electrode 5 has each of R, G, and B for two picture elements. Video signals are added sequentially. In addition, 180 conductive plates 15-1 to 15 for control electrodes 5
-n, 180 sets of video signals for one line (two picture elements per set) are simultaneously applied, and the video for one line is displayed at one time.

The horizontal focusing electrode 6 is composed of a conductive plate 17 having a plurality of vertically long slits 16 (180 slits 16) facing the slits 14 of the control electrode 5, and collects electrons for each picture element divided in the horizontal direction. Each beam is focused horizontally into a narrow electron beam.

The horizontal deflection electrode 7 is made up of a plurality of conductive plates 18, 18' arranged vertically on both sides of the slit 16, and each electrode 18, 18' has six levels of horizontal deflection. A voltage is applied to horizontally deflect the electron beam for each pixel, and on the screen 9 two sets of R,
The G and B phosphors are sequentially irradiated to emit light. In this example, the deflection range is two picture elements wide for each electron beam.

The accelerating electrode 8 is composed of a plurality of conductive plates 19 provided horizontally at the same position as the vertical deflection electrode 4, and accelerates the electron beam so that it collides with the screen 9 with sufficient energy.

The screen 9 is constructed by coating the back surface of a glass plate 21 with a phosphor 20 that emits light when irradiated with an electron beam, and adding a metal back layer (not shown). The phosphor 20 has R,
Two pairs of three-color phosphors, G and B, are provided and are applied in stripes in the vertical direction.
In FIG. 1, the broken lines drawn on the screen 9 indicate divisions in the vertical direction that are displayed corresponding to each of the plurality of line cathodes 2, and the two-dot chain lines correspond to each of the plurality of control electrodes 5. Indicates the horizontal division displayed. As shown in the enlarged view of FIG. 2, in one section partitioned by these two, there are R, G, and B phosphors 20 for two picture elements in the horizontal direction.
It has a width of 16 lines in the vertical direction. The size of one section is, for example, 1 mm in the horizontal direction,
The vertical direction is 9 mm.

Note that in FIG. 1, the length in the horizontal direction is greatly enlarged relative to the length in the vertical direction for clarity.

Further, in this example, one control electrode 5, that is, one
For the electron beam of the book, R, G, B phosphor 2
Only one pair of 0's for two picture elements is provided, but of course, one picture element or three or more picture elements may be provided, and in that case, the control electrode 5 has one picture element or three or more picture elements. R, G, and B video signals are sequentially added to the image signal, and horizontal deflection is performed in synchronization with the R, G, and B video signals.

Next, the basic configuration and waveforms of each part of a drive circuit for displaying television images on this display element will be explained with reference to FIG. First, a driving portion for irradiating the screen 9 with an electron beam to emit raster light will be described.

The power supply circuit 22 is a circuit for applying a predetermined bias voltage (operating voltage) to each electrode of the display element,
-V ₁ to the back electrode 1, and -V 1 to the vertical focusing electrodes 3 and 3'.
DC voltages of V ₃ , V ₃ ', V ₆ to the horizontal focusing electrode 6, V ₈ to the accelerating electrode 8, and V ₉ to the screen 9 are applied.

Next, a composite video signal of a television signal is applied to the input terminal 23, and a synchronization separation circuit 24 separates and extracts a vertical synchronization signal V and a horizontal synchronization signal H.

The vertical deflection drive circuit 40 includes a vertical deflection counter 25, a memory 27 for storing vertical deflection signals, and a digital-to-analog converter 39 (hereinafter referred to as a DA converter). Vertical deflection drive circuit 4
As the zero input pulse, the vertical synchronizing signal V and horizontal synchronizing signal H shown in FIG. 4 are used. The vertical deflection counter 25 (8 bits) is reset by the vertical synchronizing signal V and counts the horizontal synchronizing signal H. This vertical deflection counter 25 counts the effective scanning period (here, a period of 240H) excluding the vertical retrace period of the vertical period, and this count output is supplied to the address of the memory 27. Vertical deflection signal data (here, 8 bits) corresponding to each address is output from the memory 27, and the data is sent to the D-A converter 39 as shown in Fig. 4 (Fig. 3 b and D).
It is converted into the vertical deflection signals v and v' shown in FIG. This circuit has memory addresses that store vertical deflection signals corresponding to each line for 240H.
By storing regular data in the memory every 16 hours, a 16-step vertical deflection signal can be obtained.

On the other hand, the line cathode drive circuit 26 uses the vertical synchronization signal V and the output of the vertical deflection counter 25 to create line cathode drive pulses a to o. FIG. 5a shows the relationship between the vertical synchronizing signal V, the horizontal synchronizing signal H, and the lower five bits of the vertical deflection counter 25. FIG. 5b shows a method of creating line cathode drive pulses a' to o' every 16H using these signals. In FIG. 5, LSB indicates the lowest bit, and (LSB+1) means the bit one higher than the LSB.

The first line cathode drive pulse a' can be created by an R-S flip-flop using the vertical synchronization signal V and the output (LSB+4) of the vertical deflection counter 25, and the line cathode drive pulses b' to o' are shifted. This can be obtained by using a register to transfer the line cathode drive pulse a' using the inverted version of the output (LSB+3) of the vertical deflection counter 25 as a clock. These drive pulses a' to o' are inverted so that the potential is low only during each pulse period, and the line cathode drive pulse a is set at a high potential of about 20 volts during other periods.
~ o (Fig. 3 b and E), and each line cathode 2a
~2o added.

Each line cathode 2a to 2o is heated by a prolonged current during the high potential period of the drive pulses a to o, and the heated state is maintained so that electrons can be emitted during the low potential period of the drive pulses a to o. Ru. As a result, electrons are emitted from the 15 linear cathodes 2a to 2o only during the 16H period when low potential drive pulses a to o are applied to each of them. During the period when a high potential is applied, the potential applied to the line cathodes 2a to 2o is higher than the potential at the position of the line cathode 2 determined by the bias voltage applied to the back electrode 1 and the vertical focusing electrode 3. Since the higher potential is positive, no electrons are emitted from the line cathodes 2a to 2o. Thus, in the line cathode 2, electrons are sequentially emitted from the upper line cathode 2a toward the lower line cathode 2o for each 16H period during the effective vertical scanning period. The emitted electrons are pushed forward by the back electrode 1, and the emitted electrons are pushed forward by the back electrode 1, and the slits 1 facing each other in the vertical focusing electrode 3
0 and is focused in the vertical direction to form a flat electron beam.

Next, the relationship between the line cathode drive pulses a to o and the vertical deflection signals v and v' will be explained with reference to FIG. FIG. 6a is a waveform diagram of a line cathode pulse, b is a waveform diagram of a vertical deflection signal, and FIG. 6c is a waveform diagram of a horizontal deflection signal. The vertical deflection signals v, v' in Fig. 6b are the same as those in Fig. 6a.
During the 16H period of each line cathode drive pulse a to o of
Changes in 16-step increments of 1 hour. The vertical deflection signals v and v′ both have a center voltage of V ₄ ,
So that v increases sequentially and v' decreases sequentially,
They are designed to change in opposite directions. These vertical deflection signals v and v' are respectively applied to the electrodes 13 and 13' of the vertical deflection electrode 4, and as a result, the electron beams generated from the respective line cathodes 2a to 2o are deflected in 16 steps in the vertical direction. As mentioned earlier, on screen 9, one electron beam produces 16
The raster is deflected so as to draw one line at a time from the top.

As a result of the above, electron beams are emitted from the 15 line cathodes 2a to 2o for a period of 16 hours in order from those above them.
In addition, each electron beam is deflected one line at a time from the top to the bottom within the 15 vertical divisions, so that on the screen 9, one line is deflected from the 1st line at the top to the 240th line at the bottom. The electron beam is vertically deflected minute by minute, creating a raster of 240 lines in total.

The electron beam thus vertically deflected is horizontally deflected by 180 degrees by the control electrode 5 and the horizontal focusing electrode 6.
It is divided into sections and taken out. Figure 1 shows one of these categories. The amount of electron beam passing through each section is controlled by a control electrode 5, and horizontally focused by a horizontal focusing electrode 6 into a single narrow electron beam, which is then controlled by horizontal deflection means described below. The light is then deflected in six steps in the horizontal direction and is sequentially irradiated onto each of the R, G, and B phosphors 20 for two picture elements on the screen 9. FIG. 2 shows the vertical and horizontal divisions. The number of phosphors corresponding to each of control electrodes 5 15-1 to 15-n is 2.
For convenience of explanation, one picture element is assumed to be R ₁ , G ₁ , B ₁ and the other is assumed to be R ₂ , G ₂ , B ₂ .

Next, the horizontal deflection drive circuit 41 is composed of a horizontal deflection counter 28 (11 bits), a memory 29 storing horizontal deflection signals, and a DA converter 38. The input pulse to the horizontal deflection drive circuit 41 is synchronized with the vertical synchronizing signal V and the horizontal synchronizing signal H, as shown in FIG. 7, and uses a pulse 6H having a repetition frequency six times that of the horizontal synchronizing signal H. The horizontal deflection counter 28 is reset by the vertical synchronizing signal V and counts horizontal six times the pulse 6H. This horizontal deflection counter 28 counts 6 times during 1H and 240H×6/H=1440 times during 1V, and this count output is supplied to the address of the memory 29.
The memory 29 outputs horizontal deflection signal data (here, 8 bits) according to the address, and the D-
The A converter 38 converts it into horizontal deflection signals such as h and h' shown in FIG. 7 (FIGS. 3b and 3c). This circuit has memory addresses that store horizontal deflection signals corresponding to each of 6 x 240 lines.
By storing six pieces of regular data in the memory for each line, a six-step wave horizontal deflection signal can be obtained in a 1H period.

This horizontal deflection signal is a pair of horizontal deflection signals h and h' that change in 6 steps as shown in FIG. 7, both have a center voltage of V ₇ , and h gradually decreases.
h' increases in sequence and changes in opposite directions. These horizontal deflection signals h, h' are applied to electrodes 18 and 18' of the horizontal deflection electrode 7, respectively.
As a result, each horizontally divided electron beam is transmitted to the R, G, B,
The light is horizontally deflected so that R, G, and B (R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , B ₂ ) phosphors are sequentially irradiated for H/6 periods. Thus, in each line raster, the electron beam is divided into 180 sections in the horizontal direction.
Each phosphor 20 of R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ is sequentially irradiated with light.

Therefore, an electron beam is applied to each horizontal section of each line.
A color television image can be displayed on the screen 9 by modulating the video signals R ₁ , G ₁ , B ₁ , R _{2 ,} G ₂ , and B 2 .

Next, the modulation control portion of the electron beam will be explained. First, the television signal input terminal 23
The composite video signal applied to Combined with Y,
R, G, and B primary color signals (hereinafter referred to as R, G, and B video signals) are output. Each of these R, G, and B video signals is processed by 180 sample and hold circuits 31.
-1 to 31-n. Each sample hold circuit 31-1 to 31-n is for R1 _{and G1} , respectively.
It has 6 sample and hold circuits: 1, B ₁ , R ₂ , G ₂ , and B ₂ . Those sample and hold outputs are stored in the respective holding memories 32-1 to 32-32.
- added to n.

On the other hand, the reference clock oscillator 33 is constituted by a PLL (phase locked loop) circuit, etc., and in this example generates a reference clock 6sc of six times the color subcarrier sc and a reference clock 2sc of twice the color subcarrier sc.
The reference clock is controlled to always have a constant phase with respect to the horizontal synchronizing signal H. The reference clock 2sc is added to the deflection pulse generation circuit 42, and the signals 6H and H/6, which are six times the horizontal synchronizing signal H, are
The signal switching pulses r ₁ , g ₁ , b ₁ , r ₂ , g ₂ , b ₂ (Fig. 3b and B) are obtained for each signal switching pulse. On the other hand, the reference clock 6sc is applied to the sampling pulse generation circuit 34, where it is delayed by one clock cycle by a shift register, and is then delayed for an effective horizontal scanning period (approximately
1080 sampling pulses during 50μsec)
R ₁₁ , G ₁₁ , B ₁₁ , R ₁₂ , G ₁₂ , B ₁₂ , R ₂₁ , G ₂₁ ,
B ₂₁ , R ₂₂ , G ₂₂ , B ₂₂ ~ _{Rn 1} , Gn ₁ , Bn ₁ , Rn ₂ ,
Gn ₂ and Bn ₂ (FIG. 3b and A) are generated in sequence, and then one transfer pulse t is generated. This sampling pulse R ₁₁ ~Bn ₂ is one of the images to be displayed.
It corresponds to each picture element when a line is divided into 360 picture elements in the horizontal direction, and its position is controlled so that it is always constant with respect to the horizontal synchronizing signal H.

These 1080 sampling pulses R ₁₁ to Bn ₂ each form 180 sets of sample hold circuits 31-1.
~ 31-n, and thereby each sample hold circuit 31-1 ~ 31-n has 1
When the line is divided into 180 lines, the video signals of R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ for each two picture elements are individually sampled and held. The sample-held 180 pairs of R ₁ , G ₁ , B ₁ , R ₂ ,
The video signals of G ₂ and B ₂ are stored in 180 sets of memories 32-1 to 32-n after completing the sample hold for one line.
It is then transferred by a transfer pulse t to one moment, where it is held for the next horizontal period. This held
The signals R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ are applied to switching circuits 35-1 to 35-n. The switching circuits 35-1 to 35-n each have R ₁ ,
It is composed of a tri-state or analog gate having individual input terminals for G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ and a common output terminal for sequentially switching and outputting them.

The output of each switching circuit 35-1 to 35-n is 180 sets of pulse width modulation (PWM) circuits 37-1.
~37-n, where the reference pulse signal is pulse width modulated according to the magnitude of the sampled and held R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , B ₂ video signal and output. be done. The repetition period of the reference pulse signal is the above signal switching pulse r ₁ , g ₁ , b ₁ , r ₂ , g ₂ ,
It is desirable that the pulse width be sufficiently smaller than the pulse width of b ₂ , for example, a pulse width of about 1:10 to 1:100 is used.

The outputs of the pulse width modulation circuits 37-1 to 37-n are used as control signals for modulating the electron beam to the 180 conductive plates 15-1 of the control electrode 5 of the display element.
~15-n, respectively. The switching circuits 35-1 to 35-n are simultaneously controlled by switching pulses _r1 , _g1 , _b1 , _r2 , _g2 , _b2 applied from the switching pulse generating circuit 36. The switching pulse generation circuit 36 is controlled by the signal switching pulses r ₁ , g ₁ , b ₁ , r ₂ , g ₂ , b ₂ from the deflection pulse generation circuit 42 described above, and each horizontal period is divided into 6 Divide and switch the switching circuits 35-1 to 35-n by H/6, R ₁ ,
Each video signal of G ₁ , B ₁ , R ₂ , G ₂ , B ₂ is time-divided and outputted sequentially, and the pulse width modulation circuits 37-1 to 37-
Switching signals r ₁ , g ₁ , b ₁ , r ₂ , g ₂ ,
b Generate ₂ .

What should be noted here is that the switching circuit 3
R ₁ , G ₁ , B ₁ , R ₂ in 5-1 to 35-n,
G ₂ , B ₂ video signal supply switching and electron beams R ₁ , G ₁ , B ₁ , R ₂ ,
The horizontal deflection for switching the irradiation of G ₂ and B ₂ to the phosphor is
They are synchronously controlled to completely match both timing and order. As a result, when the electron beam is irradiating the R ₁ phosphor, the irradiation amount of the electron beam is controlled by the R ₁ video signal, and the same applies to G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ R ₁ , G ₁ , B ₁ , of each picture element are controlled by
R ₂ , G ₂ , B ₂ The emission of each phosphor is R ₁ ,
Each picture element is controlled by the video signals of G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ , and each picture element is displayed by emitting light according to the input video signal. Such control is performed simultaneously for 180 sets (2 pixels each) for one line, so that an image of 360 pixels per line is displayed, and then sequentially for 240H lines starting from the upper line. One image will be displayed.

The above operations are repeated for each field of the input television signal, and as a result,
The screen 9 is similar to a normal television receiver.
The television footage of the video is shown above.

In this way, the above image display device has 15 line cathodes 2
Since the entire image is composed of electrons independently emitted from 2 is responsible for the border of the screen (hereinafter referred to as "horizontal line")
There was a problem in that the brightness of the screen was not constant, which worsened the uniformity of the brightness of the screen.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and an object of the present invention is to provide an image display device that can suppress variations in brightness across the screen and improve image quality.

Structure of the Invention In order to achieve the above object, an image display device of the present invention includes a plurality of line cathodes that generate electron beams for each vertical section in which a screen on a screen is divided into a plurality of vertical sections, and a plurality of line cathodes that generate electron beams from the line cathodes. In an image display element having a plurality of horizontal and vertical deflection electrodes that deflect an emitted electron beam in the horizontal and vertical directions, and a vertical and horizontal focusing electrode that focuses the electron beam in the vertical and horizontal directions, the vertical focusing electrode is , a plurality of vertical focusing electrodes, and a plurality of vertical focusing electrode driving means for supplying voltage to the plurality of vertical focusing electrodes and changing the applied voltage for each scanning line.

That is, in the present invention, by increasing the voltage of one of the two vertical focusing electrodes,
By utilizing the fact that the amount of electron beam passing through the slit of the electrode increases and the brightness increases as a result,
It is designed to control brightness.

Furthermore, a similar voltage waveform is applied to the other vertical focusing electrode to offset changes in vertical deflection sensitivity due to brightness control.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 8 is a circuit block diagram of the main parts of an image display device according to an embodiment of the present invention, in which 50 is a memory;
1 is a D/A converter, and 52a and 52b are amplifiers. In this embodiment, the voltage data to be applied to one vertical focusing electrode 3 is stored in advance in the memory 50 in order to make the brightness of each scanning line constant, and the voltage data to be applied to one vertical focusing electrode 3 is stored in advance in the memory 50. The data to be stored is pulled out from the memory 50, and the D/A
The converted data is converted into analog data by the converter 51, and applied to one vertical focusing electrode 3. At the same time, a voltage waveform similar to that of one vertical focusing electrode 3 is applied to the other vertical focusing electrode 3' in a superimposed manner. That is, a signal indicated by a solid line a in FIG. 9 is applied to one vertical focusing electrode 3, and a signal indicated by a solid line b in FIG. 9 is applied to the other vertical focusing electrode 3'. Other configurations are similar to the conventional example.

The image display element of this embodiment has a characteristic that the brightness decreases when the amount of vertical deflection is large, so as shown in FIG. The power voltage waveform needs to be changed depending on the characteristics of each image display element.

The reason why voltage is applied to the other vertical focusing electrode 3' in this way is as follows. When the voltage of one vertical focusing electrode 3 changes, the vertical deflection sensitivity also changes accordingly, so in this embodiment, the voltage waveform applied to one vertical focusing electrode 3 is One vertical focusing electrode 3 is used as a brightness control electrode to control the brightness of the image display device, and the other vertical focusing electrode 3' is used to change the voltage of one vertical focusing electrode 3. It is used as a vertical deflection sensitivity compensation electrode to cancel the change in vertical deflection sensitivity caused by

Note that one scanning line is deflected horizontally by six steps in synchronization with the 6H pulse during the 1H period, but if the voltage applied to one vertical focusing electrode 3 is changed in synchronization with the 6H pulse, , it is also possible to change the color temperature of one scanning line.

Effects of the Invention As explained above, according to the present invention, the brightness of each scanning line can be controlled independently without changing the vertical deflection sensitivity, so the brightness of the entire screen can be made uniform, and horizontal lines can be detected. become less likely to be
Image quality can be improved.

[Brief explanation of the drawing]

Figure 1 is an electrode configuration diagram of a conventional image display device, Figure 2 is a diagram showing the smallest picture element on the screen, and Figure 3 is a diagram showing the smallest picture element on the screen.
The figure shows a block diagram of the drive circuit and waveform diagrams of each part,
Figure 4 is a relationship diagram between vertical deflection signals and synchronization signals, Figure 5 is a counter timing chart, Figure 6 is a relationship diagram of drive output pulses, Figure 7 is a relationship diagram between horizontal deflection signals and synchronization signals, and Figure 7 is a relationship diagram between horizontal deflection signals and synchronization signals. FIG. 8 is a circuit block diagram of the main parts of an image display device according to an embodiment of the present invention.
FIG. 9 is an output signal waveform diagram of the circuit shown in FIG. 8. 2, 2a to 2o... Line cathode, 3, 3'... Vertical focusing electrode, 4... Vertical deflection electrode, 9... Screen, 50
...Memory, 51...D/A converter, 52a, 52b
…amplifier.

Claims (1)

[Claims] 1 A screen is divided vertically into a plurality of vertical sections, each of which has a plurality of line cathodes that generate electron beams, and a plurality of horizontal and vertical lines that deflect the electron beams emitted from the line cathodes in the horizontal and vertical directions. In an image display element having a vertical deflection electrode and vertical and horizontal focusing electrodes that focus the electron beam in vertical and horizontal directions, the vertical focusing electrode is composed of a plurality of electrodes, and a voltage is applied to the plurality of vertical focusing electrodes. An image display device comprising a plurality of vertical focusing electrode driving means for supplying a voltage and changing the applied voltage for each scanning line.