JPS59151733A - Picture display device - Google Patents

Abstract

PURPOSE:To display a uniform picture as a whole while making constant the spot diameter and the spot shape of the electron beams on the screen by making voltage to be impressed on a focusing electrode to change according to a deflection quantity. CONSTITUTION:The focusing voltage to be impressed on the vertical focusing electrode 3 is made to change so as to have the higher voltage the larger quantity of vertical deflection of the part every vertical section besides the higher voltage the larger quantity of horizontal deflection of the part every horizontal section. Thereby, when the quantities of the vertical-and -horizontal deflection become large, the focal distance of a staticlens for focusing can substantially be lengthened so that, regardless of those quantities of deflection, the electron beams can be constantly focused on the surface of the screen 9(phosphor screen) so as to have the same grade of spot diameter as well as of spot shape. Accordingly, a uniform picture can be displayed on the whole screen 9 while dissolving trouble that the boundary part especially of the vertical section may be conspicuous.

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 NuClean screen is vertically divided into a plurality of divisions, and generates an electron beam for each division. The present invention relates to a device that displays a television image as a whole by vertically deflecting a plurality of lines to display a plurality of lines.

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 was impossible to create a shaped television receiver. In addition, although KL display elements, plasma display devices, liquid crystal display elements, etc. have recently been developed as flat display elements, all of them are insufficient in performance such as brightness, contrast, and color reproducibility of color display. , it has not yet been put into practical use.

Therefore, in order to achieve a flat display device using an electron beam, the present applicant has filed Japanese Patent Application No. 1983-20618 (
In JP-A No. 58-135590), a new display device was proposed.

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 a television image as a whole.

First, a basic configuration example 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, a line cathode 2 as a beam source, vertically focused FMs, 3
', a vertical deflection electrode 4, a beam flow control electrode 6, a horizontal focusing electrode 6, a horizontal deflection electrode 7, a beam acceleration electrode 8, and a NuClean plate 9 are arranged, and these are connected to a flat glass bulb (not shown). ) is housed inside a vacuum chamber.

The line cathode 2 as a beam source is stretched horizontally so as to generate an electron beam distributed linearly in the horizontal direction. In the figure, only four wires 2-2 are shown). In this embodiment, it is assumed that 15 pieces are provided. Let's call them 2i~2yo. These wire cathodes 2 are constructed by applying an oxide cathode material for thermionic emission onto the surface of a tungnuten wire having a diameter of 1Q to 20 μΦ, for example.

These linear cathodes 2A to 2Y are heated to generate a thermal electron beam by passing an electric current through them. It is controlled to emit an electron beam at a time. The back electrode 1 forms a potential gradient with a vertical focusing electrode 3, which will be described later, to suppress the generation of electron beams from other line cathodes 2 other than the line cathode 2 which is controlled to emit electron beams for a certain period of time. It also functions to push out the generated electron beam only in the forward direction. 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. In addition, these back electrode 1 and line cathode 2
Alternatively, a planar electron beam emitting electrode may be used.

The vertical focusing type ifM3 has a conductive plate 11 having a horizontally long slit 10 facing each of the line cathodes 2a to 2y.
Then, the electron beam emitted from the line cathode 2 is taken out through the slit 1Q and focused in the vertical direction. Electron beams for one horizontal line (360 pixels) are taken out at the same time.

In the figure, only one section in the horizontal direction is shown. The slits 10 may be provided with crosspieces at appropriate intervals in the middle, or may be a number of through holes provided in front at small intervals in the horizontal direction (so that they almost touch each other). Alternatively, it may be configured as a slit. The vertical focusing electrode 3' is also similar.

A plurality of vertical deflection electrodes 4 are arranged horizontally at intermediate positions of the slits 1o, and conductors 13 and 13' are provided on the upper and lower surfaces of the insulating substrate 12, respectively. It is configured. Then, a vertical deflection voltage is applied between the opposing conductors 13 and 13',
Deflect the electron beam vertically. In this embodiment, the electron beam from one line cathode 2 is vertically deflected to a position 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 16 line cathodes 2, and the electron beams are deflected to draw 240 horizontal lines on the screen 9. do.

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 predetermined intervals. In this embodiment, 180 control electrode conductive plates 15a to 15n are provided. (Only 9 lines are shown in the figure). Each of the control electrodes 5 extracts the electron beam horizontally into two sections each corresponding to two picture elements, and controls the amount of electron beam passing therethrough in accordance with the video signal for displaying each picture element.

Therefore, the conductive plates 152L to 15n for the control electrode 6 are
If 80 pixels are installed, it is possible to display 93 pixels in horizontal line spectra.In addition, in order to display images in color, each pixel must be displayed with phosphors in three colors: R, G, and B. Then, R, G, and B video signals for two picture elements are sequentially applied to each control electrode 5.

In addition, 180 conductive plates 151L to 15n for control electrodes 5
180 sets of video signals for one line (two picture elements per set) are simultaneously applied to each of the lines, 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 lines (100 lines) 16 facing the slit 14 of the control electrode 5, and each horizontally divided horizontally The electron beams for each picture element are focused horizontally into narrow electron beams.

The horizontal deflection electrode 7 includes a plurality of conductive plates 18, 1 arranged vertically on both sides of the slit 16.
．． Consisting of 8', each electric tiJi 18
118' is applied with six levels of horizontal deflection voltage to horizontally deflect the electron beam for each pixel, and sequentially illuminate each of the two sets of phosphors R, (, B) on the screen 9. Illuminate it to make it emit light.

In this embodiment, the deflection range is two picture elements wide for each electron beam.

The acceleration electrode 8 is composed of a plurality of conductive plates 19 provided horizontally at the same position as the vertical deflection electrode 4.
The electron beam is accelerated to collide with the screen 9 with sufficient energy.

Nuclean 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 thin metal back layer (not shown).

The phosphor 20 includes two pairs of phosphors of three colors R, G, and B for each slit 14 of the control electrode 5, that is, for each horizontally divided electron beam. It is 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 6. Indicates the horizontal division displayed. In one section partitioned by these two, there are phosphors 20 of R, (, B) for 2 pixels in the horizontal direction, and 16 pixels in the vertical direction, as shown in the enlarged Q in FIG. The width of one section is, for example, 18 in the horizontal direction.
゜The vertical direction is 1ow.

Note that in FIG. 1, the length in the horizontal direction is greatly expanded relative to the vertical direction to make it easier to see.

In addition, in this embodiment, only one pair of R, G, and B phosphors 20 are provided for one control chamber fM5, that is, one electron beam, for two picture elements, but of course, one picture element In this case, the control electrode 5 may be provided with one or more than three picture elements of R, G,
A B video signal is sequentially applied, and horizontal deflection is performed in synchronization with the B video signal.

Next, the basic configuration 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 explained.

The power supply circuit 22 is a circuit for applying a predetermined bias voltage (operating voltage) to each electrode of the display element, -v1 is applied to the back electrode 1, Vs, Vs', Vs', and Vs' are applied to the vertical focusing electrodes 3 and 3'.
A DC voltage of v6 is applied to the horizontal focusing electrode 6, a DC voltage of v8 is applied to the acceleration electrode 8, and a DC voltage of v9 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,
It is composed of a memory 27 for storing vertical deflection signals and a digital-to-analog converter 39 (hereinafter referred to as a single converter). As input pulses to the vertical deflection drive circuit 4o, a vertical synchronizing signal V and a 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 is counted during an effective scanning period (here, 240H) excluding the vertical retrace period of the vertical period.
This count output is supplied to an address in 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 as shown in FIG.
, v' are converted into vertical deflection signals. In this circuit, 24
There is a memory address for storing vertical deflection signals corresponding to each line of 0H minutes, and by storing regular data in the memory every 16H minutes, 16 levels of vertical deflection signals 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 [I to YO]. 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. Figure 6 shows 16 using these signals.
A method of creating line cathode driving pulses [A' to Y'] for each H will be shown.

In Figure 5, LSB indicates the lowest bit, (LSB+1)
means the bit one higher than the LSB.

The first line cathode drive PALNU [A'] can be created using an R-8 flip-flop or the like using the vertical synchronization signal V and the output (LSB+4) of the vertical deflection counter 25.
The line cathode driving pulses [A' to 'Y'] are transferred by using a shift register to transfer the green shade m drive PALNU [A'] using the inverted version of the output (LSB+2) of the vertical deflection counter 25 as a clock. Obtainable. This drive PARNU [A' to m'] is inverted and kept at a low potential only during each PARNU period, and during other periods it is converted into a line cathode drive PARNU [I to YO] which is set to a high potential of about 20 ports. , are added to each line cathode 2i to 2yo.

Each line cathode 2I to 2Y is heated by a current flowing through it during the high potential of the drive pulse [I to YO].
The heated state is maintained so that electrons can be emitted during the low potential period (I to Y). Accordingly, 15 wire cathodes 2-2
From Y to Y, electrons are emitted only during the 16H period when a low potential drive pulse [I to Y] is applied to each of them. During the period when a high potential is applied, the back electrode 1 and the vertical focusing electrode 3
Since the high potential applied to the line cathodes 2A to 2Y is more positive than the position and potential of the line cathode 2 determined by the bias voltage applied to the line cathodes 2 and 2, the line cathode No electrons are emitted from 2i to 2yo. Thus, in the line cathode 2, electrons are sequentially emitted from the upper line cathode 2a toward the lower line cathode 2y every 16H period during the effective vertical scanning period.

The emitted electrons are pushed forward by the back electrode 1, pass through the opposing nuri node 10 of the vertical focusing electrode 3, and are focused in the vertical direction to form a flat electron beam.

Next, the line cathode drive pulses [I to Y] and the vertical deflection signal v,
The relationship with v' will be explained using FIG. Vertical deflection signals v, v' are 16H of each line cathode pulse [I to Y]
During the period, it changes in steps of 1H and changes in 16 steps. The vertical deflection signals V and V' both have a center voltage of v4, and are configured to vary in opposite directions, with V increasing sequentially and V' decreasing sequentially. These vertical deflection signals V and V' are applied to the electrode 13 of the vertical deflection electrode 4, respectively.
and 13', and as a result, the electron beams generated from each of the line cathodes 2i to 2yo are vertically deflected in 16 steps, and as mentioned earlier, one electron beam is reflected on the screen 9. The raster is deflected to draw 16 lines of raster one line at a time from the top.

As a result of the above, electron beams are emitted for each 16H period from the top of the 15 line cathodes 2I to 2Y, and each electron beam is sequentially emitted for one line from top to bottom within 15 sections in the vertical direction. As a result, the electron beam is vertically deflected one line at a time on the NuClean 9 from the first line at the top end to the 240th line at the bottom end, and a total of 240 lines of raster are drawn.

The electron beam thus vertically deflected is horizontally divided into 180 sections by the control electrode 5 and the horizontal focusing electrode 6 and extracted. Figure 1 shows one of these categories. The amount of passage of this electron beam is controlled for each section by a control electrode 5, and is focused horizontally by a horizontal focusing electrode 6 into a single thin electron beam.
The light is deflected horizontally in six steps by the hydraulic deflection means described below, and is sequentially irradiated onto each of the R, G, and B phosphors 20 corresponding to two picture elements on the screen 9. FIG. 2 shows the vertical and horizontal divisions. Each of control electrodes 6 15a to 1
The phosphor corresponding to 5n is R, G, and B for two picture elements, but for convenience of explanation, one picture element is represented by 1'h, G+, and B.
+ binding and set the other side as R2, G2, and B2.

Next, the horizontal deflection drive circuit 41 is composed of a horizontal deflection force center 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.

The horizontal deflection counter 28 is reset by the vertical synchronizing signal V and counts the horizontal six-fold pulse 6H. This horizontal deflection counter 28 counts 6 times in 1H, 260 HX 6/H = 1440 times in 1V,
This count output is supplied to an address in memory 29. The memory 29 outputs horizontal deflection signal data (here, 8 bits) according to the address, and the I)-A converter 38 converts it into a horizontal deflection signal such as h' as shown in FIG. Ru.

In this circuit, there is a memory address for storing horizontal deflection signals corresponding to each of 6 x 240 lines. horizontal deflection signals can be obtained.

As shown in Fig. 7, this horizontal deflection signal is a pair of horizontal deflection signals and h' that change in 6 steps, both of which have a center voltage of v7, where h decreases sequentially and h' increases sequentially. As they progress, they change in opposite directions. These horizontal deflection signals h' are electrodes 18 and 1 of the horizontal deflection electrode γ, respectively.
8' is added.

As a result, each horizontally divided electron beam is horizontally deflected so as to sequentially irradiate the B+, G+, B1°R2r, G21, and B2 phosphors of the screen 9 for four periods during each horizontal period. . Thus, in each line of Lanuta, the electron beams are B+JG1 . B+, R2, G2, B2
Each fluorescent light #-20 is sequentially irradiated.

Therefore, for each horizontal section of each line, the electron beam is set to B+,
By modulating the video signals G+, B+, R2, G2, and B2, a color television image can be displayed on the screen 9.

Next, the modulation control portion of the electron beam will be explained.

The composite video signal applied to the mass and television signal input terminal 23 is applied to the color demodulation circuit 30, where R-Y
The color difference signals of
A B video signal) is output. Those R,G,
B Each video signal is processed by 180 sample and hold circuit sets 3
Added to 1a-31H. Each sample and hold circuit set 31a to 31n is for R1, G1, B1, and R.
It has six sample and hold circuits for G2, G2, and B2. These sample and hold circuits are each added to the holding memory set 32h and 32n.

On the other hand, the reference clock oscillator 33 is configured with a PLL (phasic loop) circuit or the like, and in this embodiment, the reference clock 6fs0 is six times as large as the color subcarrier fSC.
and double reference clock 29. occurs. The reference clock is controlled to always have a constant phase with respect to the horizontal synchronizing signal H. The reference clock 2fBc is applied to the deflection pulse generation circuit 42, and a signal 6b2 of six times the horizontal synchronizing signal H is obtained. On the other hand, the reference clock 6150 is applied to the sampling pulse generation circuit 34, where it is applied to a shift register and delayed by one clock period, etc., for an effective horizontal scanning period (63·5 μ!, ec). 10 during approximately 50μ5ec)
Eighty sampling pulses Ra1 to Bn2 are sequentially generated, and then one transfer pulse t is generated. These sibling parnu Ra+ to Bn2 correspond to each of the seven picture elements that are obtained by dividing one line of the image to be displayed into 360 picture elements in the horizontal direction, and their positions are always constant with respect to the horizontal synchronizing signal H. controlled so that

These 1000 sampling pulses Ra+P-Rn
2 are 180 sample and hold circuit sets 31a each.
.about.31n, and as a result, each sample and hold circuit set 31a to 31n has R1, G+, and R1 for each two picture elements when one line is divided into 180 pieces.
Each video signal of B1, R2, G2, and B2 is individually sampled and held.

The sample held 180 pairs of B+, G+
.

The video signals of B+, R2, G2, and B2 are stored in 180 sets of memo 1J after completing the sample hold for one line.
The signals are transferred all at once to 32a by 32nK transfer parnu t, where they are held for the next horizontal period. This retained R1. G1. B+, R2, G2, B2
The signals are applied to switching circuits 36&~35n. Each of the switching circuits 35a to 35n is B+.
, G+.

B1. It is constructed of a trinutate or analog gate having individual input terminals for R2, G2, and B2 and a common output terminal for sequentially switching and outputting them.

The output of each switching circuit 35a-35n is applied to 180 pairs of PWM width modulation (PWM) circuits 37a-37n, where it is sampled and held.
, B1. The reference pulse signal is pulse width modulated according to the magnitude of the R2, G2, and B2 video signals and is output.

The repetition period of the reference pulse signal is determined by the above signal switching P/Vs rj I CN l bj + r2 r q2
It is desirable that the pulse width of '+B2 is sufficiently small, and for example, a pulse width of about 1:10 to 1:100 is used.

The outputs of the pulse width/modulation circuits 37a-37n are individually applied to the 180 conductive plates 15a-15n of the control electrode 5 of the display element as control signals for modulating the electron beam. Each switching circuit 35aP-35ni
): Switching pulses r, l q+ + b1+ r2 applied from the Suinochinkhals generation circuit 36
+ q2 r B2 are simultaneously switched.

The switching pulse generation circuit 36 receives the signal switching pulse rj+qj+ from the deflection pulse generation circuit 42 described above.
+r2+q2+ Controlled by B2, each horizontal period is divided into 6 and the switching circuit 35 is divided into 1 month.
a Switch P-35n, lh, G1. B1+R
2, the switching signals r+ + q1+ bj + r2+ (
J2', B2 all occur.

What should be noted here is that the switching circuit 35aA
-R1 at 35n. G+, B+, R2,
G2.

B2 video signal supply switching and horizontal deflection drive circuit 41
Electron beam Ih, G1. lh, R2,
The horizontal deflection for switching the irradiation to the phosphors of G2 and B2 is
They are synchronously controlled to completely match both timing and order. With this, when the electron beam R1 is irradiated with the phosphor, the irradiation amount of the electron beam is controlled by the R1 video signal, and the G+
, B1. R2, G2, and B2 are similarly controlled, and R1, G1 . B1. R2, G2
, B2 The light emission of each phosphor corresponds to the B+ of that picture element, G1.
B1. R2.

Each picture element is controlled by the G2 and B2 video signals, and each picture element is displayed by emitting light in accordance with the input video signal. This control is 180 times for one line.
This is done simultaneously for each set (2 picture elements each) to display an image of 360 picture elements per line, and then sequentially for 240 minutes of lines starting from the upper line and displayed on screen 9.
One image will be displayed on top.

The above operations are performed on one input television signal.
The images are flipped field by field, and as a result, a moving television image is displayed on the screen 9 in the same way as in a normal television receiver.

As described above, an image is displayed in this display device. When the electron beam emitted from the line cathode 2 is deflected in the vertical and horizontal directions by the vertical deflection electrode 4 and the horizontal deflection electrode 7, In addition, the potential of the part where the electron beam passes changes depending on the amount of deflection, and as a result, when the amount of deflection is large, the horizontal focus on the screen surface 9 is poor, and the diameter and shape of the electron beam change. This causes visual horizontal lines and deteriorates the image quality. For example, in the above-mentioned display device, the screen surface 9 has a human shape as shown in FIG. 8, and there is a problem in that the vertical division boundary portions appear horizontally linear.

OBJECTS OF THE INVENTION The present invention solves these conventional problems, and when using an image display element that deflects electron beams for each section in the vertical direction and each section in the horizontal direction, the screen can also be deflected by the deflection. It is possible to maintain a good focus state of the electron beam at the top and maintain the spot diameter and shape of the electron beam in a constant state, making it possible to display uniform and good quality images with inconspicuous section boundaries. The purpose is to provide an image display device that can.

Structure of the Invention The present invention uses a nucleus having a phosphor that emits light when irradiated with an electron beam, and a screen on a screen that is vertically divided into a plurality of sections, in which an electron beam is emitted for each vertical section. An electron beam generation source consisting of a plurality of line cathodes, a focusing electrode that focuses the electron beam generated in the electron beam generation source in each vertical section, and an electrostatic charge that deflects the electron beam up to the Nuclean. shaped deflection electrode,
A display element is provided with a control electrode that controls the amount of electron beam irradiated onto the screen to control the emission intensity, and the spot diameter and shape of the spot of the electron beam on the screen generated by each line cathode are made constant. The present invention is characterized in that the voltage applied to the focusing electrode is changed in accordance with the deflection tube formed by the deflection electrode.

DESCRIPTION OF EMBODIMENTS Below, an image display device according to an embodiment of the present invention will be described.
This will be explained with reference to drawings showing the main parts thereof.

The device of this embodiment differs from the device shown in FIGS. 1 to 3 in that the voltage applied to the vertical focusing electrode 3 is
As shown in the figure, it is configured to dynamically change depending on the vertical and horizontal deflections of the electron beam.

That is, as shown in FIG.
The focusing voltage v3 applied to each vertical section is set to a higher voltage in the portion where the amount of vertical deflection is large.1. In addition, the voltage is changed in each horizontal section so that the voltage is higher in the portion where the amount of horizontal deflection is large.

A specific example of a circuit for creating such an applied voltage v5 is shown in the ninth section.
As shown in the figure. Here, 43 is the applied voltage v as shown in FIG.
Memories 44a to 44y store voltage values for each step of 5 as digital signals; The circuit 46 is a D/A converter that converts the digital signal read out from the memory 43 into an analog voltage as shown in FIG. Each of the switching circuits 44a to 44y receives a signal switching pulse rl+qj+kl++r2 from the deflection PALNU generation circuit 42.
+ 92 + b2 is added in common, and the line cathode drive pulses [A to YO] from the line cathode drive circuit 26 are applied individually to each line cathode 2A to 2E during the period when the electron beam is being emitted. By selectively operating the corresponding switching circuits 44a to 44y, a predetermined X address of the memory 43 is sequentially designated every 4 times in a 1H period. On the other hand, the Y address of the memory 43 is the count output A of the horizontal synchronizing signal H from the vertical deflection counter 26.
Add O to A7 and specify sequentially every 1H in a 16H cycle. In this way, the X address and the Y address can be specified, and digital signals at each stage of the applied voltage v3 can be read out from each address. Therefore, this read digital signal is transferred to the "/A converter 46
By performing D/A conversion, the voltage applied to the vertical focusing electrode as shown in FIG. 10 can be created. Of course, while observing the beam spot on the screen 9 in advance, the memory 43 stores the optimal applied voltage digital/digital data for each stage.
It is necessary to write the signal in advance.

In addition, if it is possible to use a voltage with almost the same waveform as the applied voltage v5 in any of the vertical sections [I to Y], the memory 43 has a storage capacity for one vertical section, and the switching circuit 44 A to 44 Y are omitted, and '2 is directly added to the signal switching pulse rj+q++k)1tr2+q2+ to the x terminal of the memory 43,
It is sufficient to read the data repeatedly in 1.6H cycles.

In this way, when voltage v3 having a waveform as shown in FIG. 10 is applied to the vertical focusing electrode 3, the focal length of the focusing electrostatic lens can be substantially lengthened when the amount of vertical and horizontal deflection becomes large. Therefore, regardless of the amount of deflection, the electron beams can always be focused on the surface of the NuClean 9 (phosphor surface) so that they have the same spot diameter and the same spot shape. Therefore, it is possible to display a homogeneous image over the entire surface of the NuClean 9, and in particular, it is possible to eliminate the inconvenience that the boundary portions of vertical sections are conspicuous.

In the above embodiment, the number of vertical divisions is 15.
Although the number of divisions in the horizontal direction was set to 180, this does not mean that the number of divisions other than this may be used. In addition, phosphors for two pixels were arranged in each horizontal section, but 1
It may be arranged one picture element at a time, or three or more picture elements each.

Further, in the above embodiment, the voltage v3 applied to the vertical focusing electrode 3 is
is changed according to the amount of deflection, but the voltage applied to other focusing type 1i3'+6 etc. may be changed.

Effects of the Invention As described above, according to the present invention, in an apparatus that displays an electron beam by generating and deflecting an electron beam for each section, the voltage applied to the focusing electrode is adjusted by the amount of deflection. By changing the spot diameter and spot shape of the electron beam on the screen to a constant value, it is possible to display an overall homogeneous image. No good display condition can be achieved.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of an image display element used in an image display device according to an embodiment of the present invention, FIG. 2 is an enlarged view of the fluorescent surface of the image display element, and FIG. A block diagram of a drive circuit devised prior to the present invention for driving, and FIGS. 4, 5, 6, and 7 are waveform diagrams of the bath section to explain the operation of the same drive circuit, respectively. , FIG. 8 is an enlarged view showing the state displayed by the drive circuit, and FIG.
The figure is a block diagram of the main parts of an image display device according to an embodiment of the present invention, and FIG. 10 is a waveform diagram for explaining the operation of the device. 2.2i~2yo...line cathode, 3,3'...
... Vertical focusing electrode, 4... Vertical deflection electrode, 5.
...Beam flow control electrode, 6...Horizontal focusing electrode, 7...Horizontal deflection type! , 9-...Nuclean board, 1o... Nulit, 20... Fluorescent material, 23... Input terminal, 24... Synchronization separation circuit, 25・・・・・・Counter for vertical deflection,
26...Line cathode drive circuit, 27...Memory, 28...Horizontal deflection counter, 29...
...Memory, 3o...Color demodulation circuit, 31a P
-31n...Sample hold circuit, 32a~
32n...Memory, 33...Reference clock oscillator, 34...Sipling parnu generation circuit, 35&P-35n...Switching circuit,
36...Nuitching pulse generation circuit, 37&
~37n...D/A converter, 4o...
Vertical deflection drive circuit, 41... Horizontal deflection drive circuit, 42... Deflection pulse generation circuit, 43...
...Memory, 44i P-44yo...Switching circuit, 46...D/A converter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Figure 11 Figure 7 Figure 8 ○○○○○○ ○○○○○○ ○O○○○○ ○○○○○○ ○○○○○○ ○○○○○○ ○○○○ ○○ ○○○○○○ ○○○○○○ ○○○○○○ ○○○○○○ ○○○O○0 0000CxD From 011m

Claims (1)

[Claims] A screen having a phosphor that emits light when irradiated with an electron beam, and a plurality of line cathodes that generate an electron beam in each vertical section where the screen on the screen is vertically divided into a plurality of sections. an electron beam generation source, a focusing electrode that focuses the electron beam generated by the electron beam generation source in each vertical section, and an electrostatic deflection electrode that deflects the electron beam until it reaches the screen. and a control electrode for controlling the emission intensity by controlling the amount of the electron beam irradiated onto the screen, and the spot diameter and shape of the electron beam on the screen generated by each of the line cathodes are provided. An image display device characterized in that a voltage applied to the focusing electrode is changed according to an amount of deflection by the deflection electrode so that the voltage is constant.