JPH0567109B2 - - 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 technology Conventionally, cathode ray tubes have been mainly used as display elements for color television image display, but conventional cathode ray tubes have a very long depth compared to the screen size, making it difficult to use in thin television receivers. It was impossible to create. 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 the electron beam vertically for each section. ,
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. 6. 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 flow control electrode 5, horizontal focusing electrode 6, horizontal deflection electrode 7, beam acceleration electrode 8
and a screen 9 are arranged, and these are housed inside a flat glass bulb (not shown) which is evacuated. 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, and takes out the electric beam emitted from the line cathode 2 through the slit 10 and directs it vertically. 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 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. 6, 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. In one section partitioned by these two, as shown in an enlarged view in FIG. 7, 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 and 9 mm in the vertical direction.

Note that in FIG. 6, the length in the horizontal direction is greatly expanded 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 0 input pulse, the vertical synchronizing signal V and horizontal synchronizing signal H shown in FIG. 9 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. 9 (Fig. 8 b, D).
It is converted into vertical deflection signals of υ and υ′ shown in . 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. 10a 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. 10b shows a method of creating line cathode drive pulses a' to o' every 16H using these signals. In Figure 10,
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. 8b, E), each line cathode 2a
~2o added.

Each of the linear cathodes 2a to 2o is heated by passing a current during the high potential periods of the drive pulses a to o, and the heated state is maintained so that electrons can be emitted during the low potential periods of the drive pulses a to o. Ru. This results in 15H
Electrons are emitted from the line cathodes 2a to 2o only during the 16H period when low potential drive pulses a to o are applied to them, respectively. 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 υ and υ' will be explained using FIG. 11. Figure 11a is a waveform diagram of the line cathode drive pulse;
b is a waveform diagram of the vertical deflection signal, and c is a waveform diagram of the horizontal deflection signal. Vertical deflection signal υ in FIG. 11b,
υ' changes by 1H in 16 steps during the 16H period of each line cathode pulse a to o in FIG. 11a.
The vertical deflection signals υ and υ' both have a center voltage of _V4 , and are configured to change in opposite directions so that υ sequentially increases and υ' sequentially decreases. These vertical deflection signals υ and υ' are applied to the electrodes 13 and 13' of the vertical deflection electrode 4, respectively, and as a result, the electron beams generated from the respective line cathodes 2a to 2o are vertically deflected in 16 steps. As mentioned earlier, on the screen 9, one electron beam sequentially scans 16 lines of raster from the top.
It is deflected to draw line by line.

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 7 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. 7 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. 12, 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 periodic signal V and counts the horizontal six times 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 (8 bits in this case) according to the address.
With the D-A converter 38, Fig. 12 (Fig. 8 b, C)
It is converted into horizontal deflection signals such as h and h' shown in FIG. 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 six steps as shown in FIG.
Both have a center voltage of V ₇ , 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. These R, G, and B video signals are processed by 180 sample and hold circuits 31-
1 to 31-n. Each sample hold circuit 31-1 to 31-n is for _R1 , _G1 ,
It has six sample and hold circuits for _B1 , _R2 , _G2 , and _B2 . These sample and hold outputs are stored in memories 32-1 to 32-n, respectively.
added to.

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 6fsc that is six times the color subcarrier fsc and a reference clock 2fsc that is twice the color subcarrier fsc.
The reference clock is controlled to always have a constant phase with respect to the horizontal synchronizing signal H. The reference clock 2fsc is added to the deflection pulse generation circuit 42, and the signals 6H and H/6, which are six times the horizontal synchronization signal H, are added to the deflection pulse generation circuit 42.
The signal switching pulses r ₁ , g ₁ , b ₁ , r ₂ , g ₂ , b ₂ (Fig. 8b, B) are obtained for each signal switching pulse. On the other hand, the reference clock 6fsc 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 during 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 ~ _{Rn 1} , Gn ₁ , Bn ₁ , Rn ₂ ,
Gn ₂ and Bn ₂ (FIG. 8b, 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.
Each corresponds to a 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.
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.

Problems to be Solved by the Invention The image display device described above does not use a high voltage of around 20KV like the conventional 10-inch size CRT, but uses an applied voltage of around 10KV, which is about 1/2 of that of the conventional 10-inch CRT. In order to obtain the same brightness as a CRT, one of the phosphors on the screen corresponding to the signal electrode is
The electron beam is designed to irradiate one (RGB one) up to the maximum irradiation time (1/number of horizontal deflection stages) with a horizontal period of 64 μs. Now, if the number of horizontal deflection stages is 3, the time that the electron beam irradiates one phosphor is about 20 μs. Compared to this,
In a conventional CRT, the time for the electron beam to irradiate one phosphor is (64 μs/total number of pixels in one horizontal period)
For a 10-inch size, it is approximately 0.1 μs, which is 1/20 of the irradiation time of the above image display device.
It has also become 0. For this reason, the image display device proposed earlier has 200 times better brightness than conventional CRTs when only the beam irradiation time is taken into account, and even if the high voltage is reduced to half, it will still be brighter than conventional CRTs. do
It has to be about 70 times brighter. here,
Since the electron densities of the beams are approximately the same, they will be excluded from consideration. However, in reality, the brightness is only about half that of a conventional CRT, and there is a problem in that the increase in electron beam irradiation time has almost no effect. This is because the phosphor coated on the screen has its own afterglow property, so even if it is irradiated with an electron beam for a minute time, it will continue to shine for several milliseconds, so even if it is irradiated for 0.1 μs, it will continue to shine for several milliseconds. Even if it is irradiated for 10 μs, it seems to have little effect on brightness because it is small compared to the afterglow time.

This situation is shown in FIG. The solid line is the brightness change characteristic of a conventional 10-inch CRT, and the broken line is the brightness change characteristic of the image display device that we proposed earlier. Since the average brightness perceived visually is the integral of this, it is understandable that it is approximately 1/2 that of a conventional CRT.

The present invention solves the above-described lack of brightness and provides an image display device that can obtain brightness equivalent to or even higher than conventional CRTs.

Means for Solving the Problem In order to solve this problem, the image display device of the present invention reduces the phosphor at one selected position by half.
The beam is irradiated with a period of field time (approximately 8 msec), and the beam flow control electrode of the previously proposed device is placed at the point where the number of horizontal scanning lines is divided into two, that is, at the center of the screen, and at the top and bottom. divided into
Furthermore, by applying a signal shifted by 1/2 field to each of the upper and lower electrodes, normally the signal applied to the upper beam flow control electrode is delayed by 1/2 field than the signal applied to the lower beam flow control electrode. The system is designed to display an image of approximately 120H (1 /2 effective vertical field period) using a latch circuit, and
The voltage is applied to each divided beam flow control electrode.

Function As mentioned above, the period at which the electron beam irradiates the phosphor on the screen is 8 msec (1/2
2 field time), which is half the 16.6 msec of conventional CRTs and image display devices proposed earlier, so the irradiation time of the phosphor with the electron beam is approximately doubled. do.

Embodiment An embodiment of the present invention will be described below based on the drawings. The main parts of the present invention are two points: changing the electrodes of the image display device and changing the circuit that drives the electrodes.

First, we will explain how to change the electrodes. Beam flow control electrode 5 as a signal modulation electrode that we proposed earlier
As shown in Figure 3B, 1 corresponds to the R, G, and B phosphors from top to bottom in the vertical direction of the screen.
It was composed of sets of conductive plates 15-1 to 15-n. In the present invention, as shown in FIG. 3A, this is constituted by two sets of conductive plates divided into two at the center in the vertical direction. It is considered to be separate.

As you can see in this figure, it is divided at the center of the screen (if the conventional effective screen area is 240H (x 2) vertically, then the middle of 120H and 121H), SU, SD
Two types of signal modulation electrodes are used. Here, 103
104 indicates the effective screen portion of the screen, and 104 indicates the center portion of the screen.

Next, a specific example of the drive circuit is shown in FIG. 1st
The figure shows a processing unit for one of the primary color signals (for example, R), and in reality, as can be seen from the drive circuit of the image display device proposed earlier, three The two primary color signals are mixed, but the details are omitted.

In FIG. 1, 201 is an input primary color signal (either R, G, or B), and this primary color signal is A
- It is input to the D conversion circuit 202 and converted into digital data, and this data is stored in the 1H memory 203 and
The signals are input to the 120H memory 204 in parallel. The signals input to the 1H memory 203 are written in time sequential manner by the latch start pulse 205, and are transferred to the next stage 1H memory 207 in horizontal cycles by the data transfer pulse 206 during horizontal blanking. The process is exactly the same as that of the drive circuit block proposed in 2003. Next, 120H memory 2
04 is a latch memory with a shift register configuration.
The output data of the 120H memory 204 is driven by the latch start pulse 205 and the enable pulse 209 so that when the vertical effective screen is 240H, the data is always delayed by 120H from the data input to the 1H memory 203. 1H memory 210, 2 connected after the 120H memory 204
Reference numeral 11 is the same as the 1H memories 203 and 207 described above, that is, the drive circuit block proposed earlier.
Therefore, from the PWM converters 208 and 212, the SU- corresponding to the respective conductive plates of the beam flow control electrodes 101 and 102 is transmitted via the changeover switches 214-1 to 214-2 operated by the signal changeover switching pulse 213. Signals 1 to SU-n and SD-1 to SD-n appear alternately every 120H period.

FIG. 2a shows the relationship between each applied pulse, and FIG. 2b shows an enlarged view of the latch start pulse 205 and the data transfer pulse 206 during the 1H period.

In this way, the beam flow control electrode is
By dividing the electron beam into two parts and by irradiating the upper and lower beam flow control electrodes with an electron beam modulated at a 1/2 field period, the brightness can be improved compared to the previously proposed image display device. , it is possible to achieve approximately twice the brightness, making it possible to obtain a brightness comparable to that of conventional CRTs. This situation is shown in FIG. As can be seen from this figure, it is easy to obtain the integrated value of luminance over time, that is, the average luminance, with the present invention comparable to that of a conventional CRT.

Effects of the Invention As described above, according to the present invention, since the phosphor at one selected position is irradiated with a beam at a period of 1/2 field time, the time is approximately twice that of the previously proposed image display device. This can solve the problem of lack of brightness.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of the main part showing one embodiment of the present invention, FIG. 2 is a waveform diagram showing its timing, and FIG.
Figures A and B are front views of the present invention and the conventional beam flow control electrode, Figure 4 is a characteristic diagram showing the effects of the present invention in comparison with the conventional one, and Figure 5 is the conventional CRT and the previously proposed image display device. 6 is a diagram showing the basic electrode configuration of the previously proposed image display device. FIG. 7 is a diagram showing the minimum unit configuration of the present image display device on the screen. Figure 8 is a block diagram of the drive circuit and waveform diagrams of various parts in the same device, Figure 9 is a correlation diagram between vertical deflection voltage and horizontal synchronizing signal, Figure 10 is a diagram of various timing charts, Figure 11 is a cathode drive pulse, A diagram showing the relationship between the vertical deflection signal and the horizontal deflection signal, and FIG. 12 is a diagram showing the correlation between the horizontal deflection voltage and the horizontal synchronizing signal. 2, 2a to 2o... Line cathode, 4... Vertical deflection electrode, 7... Horizontal deflection electrode, 9... Screen, 2
0... Fluorescent substance, 101, 102... Beam flow control electrode, 202... A-D conversion circuit, 203, 20
7...1H memory, 204...120H memory, 20
5... Latch start pulse, 206... Data transfer pulse, 208... PWM converter, 209...
...Enable pulse, 210, 211...1H memory, 212...PWN converter, 214-1 to 2
14-2...Switching switch.

Claims (1)

[Claims] 1. A screen coated with a phosphor that emits light when irradiated with an electron beam; an electron beam source that generates an electron beam for each vertical division of the screen on the screen;
separation means for dividing the electron beam generated by the electron beam source into a plurality of horizontal sections and irradiating the separated beam onto the screen; A beam flow that controls the amount of light emitted from each pixel on the screen by controlling the amount of the electron beam irradiated onto the screen with a deflection electrode that deflects in a plurality of steps in the horizontal direction, and the electron beam separated for each horizontal section. a control electrode, a focusing electrode for controlling the size of light emitted by the electron beam on the phosphor surface in each pixel, a back electrode for controlling the amount of electron beam from the electron beam source, and an accelerated irradiation of the electron beam to the screen. an accelerating electrode, and the beam flow control electrode is vertically divided into upper and lower portions at a position corresponding to the position where the number of horizontal scanning lines is divided into two, and a signal shifted by 1/2 field is sent to each of the upper and lower beam control electrodes. An image display device having means for applying voltage in line sequential manner corresponding to horizontal synchronization.