JPH0434255B2 - - 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, in order to achieve a flat display device using electron beams, the present applicant filed a patent application in 1983-
No. 20618 (Japanese Unexamined Patent Publication No. 135590/1983) proposed a new display device.

This method generates an electron beam for each section when the screen is vertically divided into multiple sections, and displays multiple lines by deflecting each electron beam vertically for each section. However, it displays the 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', vertical deflection electrode 4, beam current control electrode 5,
It consists of a horizontal focusing electrode 6, a horizontal deflection electrode 7, a beam accelerating electrode 8, and a screen 9, which are arranged in a flat glass bulb (not shown).
The interior is housed in a vacuum. 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 by passing an electric current through them, and as described later, emit electron beams sequentially for a certain period of time starting from the line cathode 2a. controlled as follows. 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 embodiment, the electron beam from one line cathode 2 is vertically deflected to positions corresponding to 16 lines 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 each consist of a conductive plate 15 having a vertically long slit 14, and a plurality of control electrodes 15 are arranged horizontally 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 are shown. ) Each of the control electrodes 5 extracts the electron beam horizontally by dividing it into two picture elements each, 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 embodiment, 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'.
V ₃ , V ₃ ′, V ₆ for the horizontal focusing electrode 6, acceleration electrode 8
A DC voltage of V ₈ is applied to the screen 9, and a DC voltage of V ₉ is applied to the screen 9.

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. The memory 27 outputs vertical deflection signal data (here, 8 bits) corresponding to each address, and the D-A converter 39 outputs the vertical deflection signal data (8 bits in this case) as shown in FIG.
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. 3b, E), 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 drive 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.
During the 16H period of each line cathode pulse a to o in figure a
Changes in 1H increments to 16 steps. Both vertical deflection signals v and v′ have a center voltage of V ₄ , and v
are made to change in opposite directions so that v' increases sequentially and v' decreases sequentially. These vertical deflection signals v and v' are applied to the vertical deflection electrode 4, respectively.
As a result, the electron beams generated from the respective line cathodes 2a to 2o are vertically deflected in 16 steps, and as mentioned above, one electron beam is formed on the screen 9. The raster is deflected so that 16 lines of raster are drawn 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 phosphors corresponding to 15-1 to 15-n of the control electrode 5 are R, G, and B for two picture elements, but for convenience of explanation, one picture element is R ₁ , G ₁ , and B _{1 and the other is R 1 , G 1 , and B 1} . Let R ₂ , G ₂ , and 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-
In the A converter 38, h shown in FIG. 7 (FIG. 3 bC),
It is converted into a horizontal deflection signal such as h′. This circuit has memory addresses for storing horizontal deflection signals corresponding to each of 6 x 240 lines, and by storing 6 pieces of regular data for each line in the memory, 6 step waves are generated in 1H period. horizontal deflection signals can be obtained.

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
Furthermore, they are combined with the luminance signal Y, R,
G and B primary color signals (hereinafter referred to as R, G and B video signals) are output. These R, G, and B video signals are processed by 180 sets of sample and hold circuits 31-1 to 31-1.
31-n. Each sample hold circuit 31-1 to 31-n is for _R1 , _G1 , and _B1.
It has 6 sample and hold circuits: 1, R ₂ , G ₂ , and B ₂ . These sample and hold outputs are respectively applied to holding memories 32-1 to 32-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
Signal switching pulse per r ₁ , g ₁ , b ₁ , R ₂ , g ₂ , b ₂
(Fig. 3b, B) pulses are obtained. On the other hand, the reference clock 6sc is the sampling pulse generation circuit 34.
is added to the 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 ~ _Ro1 , _Go1 , _Bo1 , _Ro2 ,
G _o2 and B _o2 (FIG. 3b, a) are generated in sequence, and then one transfer pulse t is generated. This sampling pulse R ₁₁ ~B _o2 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 B _o2 are each connected to 180 sample and 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.
are transferred all at once by a transfer pulse t, and held here 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. 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 and divided into H/6. Switch the switching circuits 35-1 to 35-n one by one,
Each video signal of R ₁ , 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 3
Switching signals r ₁ , g ₁ , b ₁ ,
Generate r ₂ , g ₂ , b 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 of one line (2 picture elements each), so that an image of 360 picture elements per line is displayed, and then sequentially for 240 H of 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.

However, in conventional line cathode drive circuits,
As shown in Figure 8A, the emission current i _e is the line cathode 2
flows in one direction (arrow), creating a potential gradient ΔV there. Normally, this potential gradient ΔV is about 1 V, so the energy of the electrons emitted from the line cathode 2 entering the vertical deflection lens system varies greatly, and
In the case of Figure A, the energy increases and the entry speed increases as you go to the left side of the linear cathode 2. Therefore, the vertical deflection sensitivity of the electrostatic vertical deflection electrode 4 is reduced, and the seams of the vertical sections differ greatly in the left and right directions of the line cathode 2, resulting in a disadvantage that they are very noticeable. This situation is shown in FIG. 8B.

In FIG. 8A, 50 is a switching transistor for supplying a heating current to the line cathode 2, and 51 is a switching transistor for passing an emission current to the line cathode 2.

OBJECTS OF THE INVENTION The present invention obviates such drawbacks and
The purpose is to reduce the difference in the appearance of the joints of each vertical section in the line cathode direction, and to obtain a uniform image in the vertical direction as a whole screen.

Structure of the Invention The image display device of the present invention divides a part of the focusing electrode, which affects the vertical deflection sensitivity, into a plurality of parts in the horizontal direction in response to the voltage drop that occurs in the line cathode when an electron beam is generated. A voltage is applied to both ends of the divided concentrating electrodes so that the concentrating electrode corresponding to the drive side of the linear cathode has a lower potential, and the potential distribution by the divided concentrating electrodes is changed in stages. This structure allows for the reduction of some of the large seams between each vertical section.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings. In FIG. 9, the vertical focusing electrode 3' is divided into a plurality of parts in the horizontal direction, and one end of these divided focusing electrodes 3'' is taken out as a terminal outside the glass bulb.
Each divided focusing electrode 3'' is connected by resistors Ro to Rn, and a potential difference (E _{0 −E 1 ) is applied from the outside so that the side corresponding to the driving side of the linear cathode 2 has a low potential (E 0} −E ₁ ).The vertical focusing electrode 3 The division ' is formed on the side where there is a large seam between each vertical section.As a result, as the divided focusing electrode 3'' goes to the left in the figure, the voltage is divided by the resistors Ro to Rn, and the voltage gradually decreases. go. This situation is shown in FIG. In this embodiment, the value of each resistor Ro to Rn is several tens of ohms, and the appropriate number of divisions is approximately 100 divisions from the left end of the screen. At this time, the potential gradient E ₀ to E ₁ is about 10V. Reference numeral 10' denotes a vertical slit provided in the focusing electrodes 3', 3'' facing each of the line cathodes.

As shown in FIG. 10, the potential distribution of the vertical focusing electrode changes stepwise to become lower toward the left side due to the division, so that the vertical deflection sensitivity increases toward the left side of the screen. As a result, the deterioration in vertical deflection sensitivity on the left side caused by the potential gradient where the left side has a low potential due to the emission current of the line cathode 2 is corrected, and as shown in FIG. It can be seen that it has been greatly reduced. Further, by arbitrarily selecting the resistance value and the value of the potential gradient E ₀ to _{E 1} , it is possible to perform correction in various forms, so that correction can be performed over a relatively wide range. In this embodiment, only the left side of the vertical focusing electrode 3' is divided in order to correct only the left side of the screen of the image display device, but by dividing the entire vertical focusing electrode 3' in the horizontal direction, the entire screen can be corrected. It is clear that it is possible to correct the

Effects of the Invention As described above, according to the present invention, the focusing electrode corresponding to the side where the seam between each vertical section is large is divided into a plurality of parts in the horizontal direction, and each divided focusing electrode is connected with a resistor. By applying a voltage, the potential of the divided focusing electrode can be created arbitrarily, and the vertical deflection position of the electron beam on the screen can be accurately corrected.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the basic electrode configuration of an image display device to which the present invention is applied, FIG. 2 is a diagram showing the configuration of the minimum unit on the screen, and FIG. 3 is a block diagram of the drive circuit of the device. Waveform diagrams of each part, Figure 4 is a correlation diagram between vertical deflection voltage and horizontal synchronizing signal, Figure 5 is a diagram of various timing charts, and Figure 6 is a waveform diagram showing the relationship between cathode drive pulse, vertical deflection signal, and horizontal deflection signal. , FIG. 7 is a correlation diagram between the horizontal deflection voltage and the horizontal synchronizing signal, FIG. 8 is a diagram for explaining the problems of the conventional image display device, and FIG. 9 is an image display device in an embodiment of the present invention. FIG. 10 is a diagram showing the potential gradient due to the divided focusing electrode of the present invention, and FIG. 11 is a diagram for explaining the correction effect using the present invention. 1... Back electrode, 2, 2a to 2o... Line cathode,
3'... Vertical focusing electrode, 3''... Divided focusing electrode, 4
... Vertical deflection electrode, 5 ... Beam current control electrode,
7...Horizontal deflection electrode, 9...Screen, 10'
...Slit, 20...phosphor, Ro~Rn...resistance.

Claims (1)

[Claims] 1. A screen coated with a phosphor that emits light when irradiated with an electron beam, and a line cathode as an electron beam source that generates an electron beam in each vertical section of the screen on which the screen is vertically divided. and separation means for dividing the electron beam generated by the line cathode into a plurality of horizontal sections and irradiating the separated beam onto the screen; and a deflection electrode that deflects horizontally in multiple stages, and a signal that controls the amount of light emitted from each pixel on the screen by controlling the amount of electron beams separated for each horizontal section irradiated onto the screen. an electrode, a focusing electrode that controls the size of light emitted by the electron beam on the phosphor surface in each pixel, and a back electrode that controls the amount of the electron beam generated,
A part of the focusing electrode, which affects the vertical deflection sensitivity, is divided horizontally into a plurality of parts in response to the voltage drop that occurs in the line cathode when an electron beam is generated, and each divided electrode is connected with a resistor, By applying an external voltage so that the concentration electrode corresponding to the driving side of the linear cathode has a lower potential among the concentration electrodes that have been divided, the potential of the divided focusing electrodes is changed stepwise based on the value of the resistor. An image display device designed to change to