JPS6190578A - Picture display device - Google Patents

Abstract

PURPOSE:To change a visual spot diameter while an ideal beam spot shape is held and to obtain a uniform beam spot shape over the entire screen by changing the landing position of an electron beam on the screen by trace amount with the aid of a high frequency signal. CONSTITUTION:A triangular wave generated in a high frequency wave oscillation part 47 modulates a vertical deflecting signal nu0 from a deflection processing part 44, while a triangular wave whose phase is shifted by 180 deg. in a phase shifting part 48 modulates a vertical deflecting signal nu0'. Thus the spot position of an electron beam an a screen changes vertically from a steady position on each line corresponding to the amplitude of the triangular wave. Due to a high speed, said change is visually equivalent to such a case where the diameter of the beam spot in the vertical direction is steadily enlarged.

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 was impossible to create a television receiver for Furthermore, as flat display elements, EL display elements, plasma display devices, liquid crystal display elements, etc. have recently been developed.

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, we aimed to achieve a flat display device using electron beams, and when the screen on the screen is vertically divided into multiple sections, an electron beam is generated for each section. It was invented to display a plurality of lines by vertically deflecting each electron beam to display a television image as a whole.

First, the basic one-groove 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 beam source, vertical focusing electrode (3) (
3'), vertical deflection electrode (4), beam current control voltage Vi (5
), a horizontal focusing electrode (6), a horizontal deflection electrode (7), a beam accelerating electrode (8), and a screen (9), which are placed in the vacuum of a flat glass bulb (not shown). Made inside. 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, and a plurality of line cathodes (2) are arranged vertically at appropriate intervals. Book(
In the figure, four (2a) to (2d) are shown). 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. And these line cathodes (2a) to (20
) is heated so as to generate a thermionic electron beam by passing an electric current through it, and as described later, it is controlled to emit an electron beam sequentially for a fixed period of time starting from the line cathode (2a). . The back electrode (1) suppresses the generation of electron beams from other line cathodes other than the line cathode that is controlled to emit electron beams for a certain period of time, and directs the generated electron beams only in the forward direction. It has the effect of pushing out toward the target. This back electrode (1) may be formed by a coating of electrically conductive material applied to the inner surface of the rear wall of the crow bulb. Furthermore, a one-plane electron beam emitting cathode may be used instead of the back electrode (1) and the line cathode (2).

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 collects the electron beam emitted from the line cathode (2). taken out through the slit (10),
and vertically focused. 1 horizontal line (3
60 pixels worth of electron beams are taken out at the same time. In the diagram,
Of these, 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 row of through holes provided in large number at small intervals in the horizontal direction (intervals that are almost touching). It may be configured substantially as a slit. The vertical focusing electrodes (3') are also similar6. A plurality of vertical deflection electrodes (4) are arranged horizontally at intermediate positions of the slits (10),
Conductors (
13) (13') is provided. Then, a vertical deflection voltage is applied between the opposing conductors (13) (13') to deflect the electron beam in the vertical direction. In this example, a pair of conductors (13) (1
3') deflects the electron beam from one line cathode (2) vertically to positions corresponding to 16 lines.

The 16 vertical deflection electrodes (4) constitute 15 conductor pairs corresponding to each of the 15 line cathodes (2), so that 240 horizontal lines are drawn on the screen (9). Deflect the electron beam to

Next, the control electrodes (5) are composed of conductive plates (15) each having a long slit (14) in the vertical direction, 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 (15-1)
~(15-n) are provided. (Only 9 lines are shown in the figure). Each of the control electrodes (5) separates and extracts the electron beam into two picture elements in the horizontal direction, and controls the amount of electron beam passing therethrough in accordance with a video signal for displaying each picture element. Therefore, if 18080 conductive plates (15-1) to (15-n) for control electrodes (5) are installed, one horizontal
360 picture elements can be displayed per line. In addition, in order to display images in color, each picture element is R, G, B
Each control electrode (5)
R2O and B video signals for two picture elements are sequentially added to the . In addition, 180 control electrodes (5) conductive plates (15-
1) to (15-n) each has 180 pixels for one line.
Groups (2 picture elements per 1' group) of video signals are applied simultaneously, and one line of video is displayed at one time.

The horizontal focusing electrode (6) is connected to the slit (14) of the control electrode (5).
) is composed of a conductive plate (17) having a plurality of vertically long slits (16) facing each other, and the electron beam for each pixel divided horizontally is transmitted horizontally. Focus into a narrow beam of electrons.

The horizontal deflection electrode (7) is composed of a plurality of conductive plates (18) (18') arranged vertically on both sides of the slit (16), and each electrode (18) ( 18') is applied with six levels of horizontal deflection voltage to deflect the electron beam of each picture element in the horizontal direction, so that two sets of R and G are displayed on the screen (9).

Each phosphor of B is sequentially irradiated to emit light. In this example, the deflection range is two picture elements wide for each electron beam.

The accelerating electrode (8) is composed of a plurality of conductive plates (19) installed horizontally at the same position as the vertical deflection electrode (4), and allows the electron beam to collide with the screen (9) with sufficient energy. Accelerate as if

The screen (9) is made up of a phosphor (20) that emits light when irradiated with an electron beam, which is coated on the back surface of a glass plate (21), and a metal back layer (not shown) is added. The body (20) has two pairs of phosphors of three colors R2O 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 vertical divisions displayed corresponding to the plurality of line cathodes (2), and the two-dot chain lines indicate the divisions in the vertical direction that are displayed corresponding to the plurality of line cathodes (2). ) shows the horizontal divisions displayed corresponding to each of them. As shown in the enlarged view in Figure 2, one section partitioned by these two has R, G, and B phosphors (20) for two pixels in the horizontal direction, and 16 lines in the vertical direction. It has a width of 30 minutes. The size of one section is, for example, IIffI+ in the horizontal direction and 91 m in the vertical direction.

Note that in FIG. 1, the length in the horizontal direction is drawn much thicker than in the vertical direction for clarity. 'Also, in this example, only one pair of R, G, and B phosphors (20) for two picture elements is provided for one control electrode (5), that is, for one electron beam. Of course, one picture element or three picture elements or more may be provided, and in that case, the control electrode (5) has R for one picture element or three picture elements or more.
, G, and B video signals are applied sequentially, and horizontal deflection is performed in synchronization with them.

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 explained.

The power supply circuit (22) is a circuit for applying a predetermined bias voltage (operating voltage) to each electrode of the display element.
-■0 for 1), V3. for vertical focusing electrode (3) (3'). V3', horizontal focusing electrode (6) is equipped with an accelerating electrode (
8) A DC voltage of Vs is applied to the screen (9).

Next, a composite video signal of a television signal is applied to the input terminal (23), and a vertical synchronization signal V and a horizontal synchronization signal H are separated and extracted in a synchronization separation circuit (24).

The vertical deflection drive circuit (40) includes a vertical deflection counter (2
5), a memory for vertical deflection signal storage (27), and a digital-to-analog converter (30) (hereinafter referred to as a DA converter). As input pulses to the vertical deflection drive circuit (40), a vertical synchronizing signal V and a horizontal synchronizing signal H shown in FIG. 4 are used. Vertical deflection counter (25) (
8 bits) are reset by the vertical synchronizing signal V and counting the horizontal synchronizing signal H.

This vertical deflection counter (25) counts the effective scanning period (in this case, 240H) excluding the vertical retrace period of the vertical period, and this count output is sent to the address of the memory (27). Supplied. The memory (27) outputs vertical deflection signal data (here, 8 bits) corresponding to each address, and the D-A converter (39) outputs the data of the vertical deflection signal corresponding to each address.
The signal is converted into the vertical deflection signals of A and B' shown in the figure (FIG. 3(b)D). This circuit has memory addresses for storing vertical deflection signals corresponding to each line for 240H, and by storing regular data in the memory every 16H, it is possible to obtain 16 levels of vertical deflection signals. can.

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-o. FIG. 5(a) shows the vertical synchronization signal ■,
The relationship between the horizontal synchronizing signal H and the lower 5 bits of the vertical deflection counter (25) is shown. FIG. 5(b) shows a method of creating line cathode driving pulses a' to 0'' every 16H using these signals. In FIG. 5, LSB indicates the Q low bit, and (LS B + 1 ) means the bit one higher than the LSB.

The first line cathode drive pulse a' can be created by an R-S flip-prop using the vertical synchronization signal V and the output (LSB+4) of the superposed deflection counter (25), and the line cathode drive pulse b'~ 0' uses a shift register,
This can be obtained by transferring the line cathode drive pulse a' using the inverted version of the output (LSB+3) of the vertical deflection counter (25) as a clock. This drive pulse aI
,,ol is inverted and brought to a low potential only during each pulse period,
During other periods, it is converted into line cathode driving pulses a~0 with a high potential of about 20 volts (Fig. 3(b) E).
, are added to each line cathode (2a) to (2o).

Each line cathode (2a) to (2o) is heated by a prolonged current during the high potential period of the drive pulses a to 0, and is heated so that electrons can be emitted during the low potential period of the drive pulses a to 0. State is preserved. As a result, 15 wire cathodes (2a)
From ~(20), low potential drive pulses a~0 are respectively obtained.
Electrons are emitted only during the 16H period when . During the period when a high potential is applied, the line cathode (2a ) to (20) is more positive, so 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) to the lower line cathode (20) for 16H periods during the effective vertical scanning period. The emitted electrons are pushed forward by the back electrode (1), pass through the opposing slits (10) of the vertical focusing electrode (3), and are focused in the vertical direction, forming a flat plate of electrons. Becomes a beam.

Next, the line cathode drive pulse a′=o and the vertical deflection signal ν
, l will be explained using FIG.

FIG. 6(a) is a waveform diagram of a line cathode pulse, FIG. 6(b) is a waveform diagram of a vertical deflection signal, and FIG. 6(c) is a waveform diagram of a horizontal deflection signal. The vertical deflection signal ν, 9' in FIG. 6(b) is as shown in FIG. 6(a).
During the 16H period of each line cathode drive pulse a to 0, the line cathode drive pulse changes by IH in 16 steps.

Vertical deflection signals ya and kan'' both have a center voltage of v4, ν increases sequentially, and 9' decreases sequentially.
They are designed to change in opposite directions. These vertical deflection signals ν and ν' are respectively applied to the electrodes (13) and (13') of the vertical deflection electrode (4), resulting in the electron beams generated from the respective line cathodes (2a) to (2o). is vertically deflected in 16 steps.

As mentioned above, one electron beam is deflected on the screen (9) so that a raster of 16 lines is drawn sequentially one line at a time from the top.

As a result of the above, electron beams are emitted for 16H periods in order from the one above the 15 line cathodes (2a) to (2o).

Each electron beam is deflected one line at a time from top to bottom within 15 sections in the vertical direction, so that on the screen (9), from the first line at the top to the second line at the bottom.
The electron beam is vertically deflected one line at a time up to the 40th line, and a raster of 240 lines in total is drawn.

The vertically deflected electron beam is connected to the control electrode (5).
It is divided into 180 sections in the horizontal direction by a horizontal focusing electrode (6) and taken out. In Figure 1, one of them
The classification is shown. The amount of electron beam passing through each section is controlled by a control electrode (5), and is focused in the horizontal direction by a horizontal focusing electrode (6) to become one narrow electron beam.

The light is deflected horizontally in six steps by the horizontal deflection means described in the next section, and is sequentially irradiated onto each of the R2O and B phosphors (20) for two picture elements on the screen (9). The phosphors corresponding to each of (15-1) to (15-n) of the six control electrodes (5) whose vertical and horizontal divisions are shown in Figure 2 are R, G, and B for two picture elements. For convenience of explanation, one picture element is R1,
G1. B, and the other one is R2, G, , B2.

Next, the horizontal deflection drive circuit (41) is composed of a horizontal deflection counter (29) (11 bits), a memory (29) that stores horizontal deflection signals, and a D-A converter (38). . The input pulses of the horizontal deflection drive circuit (41) are the vertical synchronizing signal ■ and the horizontal synchronizing signal H, as shown in FIG.
A pulse 6H with a repetition frequency six times that of the horizontal synchronizing signal H is used. The horizontal deflection counter (28) is reset by the vertical synchronizing signal V and receives the horizontal six times the pulse 6.
Count H. This horizontal deflection counter (28) is applied 6 times during IH and 240Hx6/H=14 during 1V.
Count 40 times, and this count output is stored in memory (29)
address.

The horizontal deflection signal data (here, 8 bits) corresponding to the address is output from the memory (29), and is processed by the D-A converter (38) as shown in Fig. 7 (Fig. 3 (b) C). ,h
' is converted into a horizontal deflection signal such as '. In this circuit, 6
There is a memory address for storing the horizontal deflection signal corresponding to each of the 240 lines, and by storing 6 pieces of regular data for each line in the memory, a 6-step wave horizontal deflection signal is generated during the IH period. can be obtained.

As shown in Fig. 7, this horizontal deflection signal is a pair of horizontal deflection signals ri and h' that change in 6 steps, both of which have a center voltage of v7, where h decreases sequentially and h' increases sequentially. They change in opposite directions as they move forward. These horizontal deflection signals, h' are the electrode (1) of the horizontal deflection electrode (7), respectively.
8) and (18'). As a result, each horizontally segmented electron beam is applied to the R, G of the screen (9) during each horizontal period.

B, R, G, B (R,, al, B□, Rz-G2.B
The light is horizontally deflected so that the phosphor of 2) is sequentially irradiated for H/6 periods. Thus, in the raster of each line, the electron beam is divided into R and G for each of the 180 sections in the horizontal direction.
1. B1. Each of the R, G, B2 phosphors (20) is sequentially irradiated.

Therefore, the electron beams are set to R, , G for each horizontal section of each line.
□, B1. R,,G2. By modulating the video signal of B, a color television image can be displayed on the screen (9).
] Next, the modulation control portion of the electron beam will be explained. First, the composite video signal applied to the television signal input terminal (23) is applied to the color demodulation circuit (30),
Here, the R-Y and B-Y color difference signals are demodulated, and the G-Y
The color difference signals are combined as a madrisk signal, and further, they are combined with the luminance signal Y to output R2O and B primary color signals (hereinafter referred to as R, G, and B video signals). Those R
, G, and B video signals are applied to 180 sets of sample and hold circuits (31-1) to (31-n). Each sample hold circuit (31-1) to (31-n) is connected to R
, Gi, B1, R2, G2, and B2. Those sample and hold outputs are stored in the holding memories (32-1) to (32-1).
32-n).

On the other hand, the reference lock oscillator (33) is composed of a PLL (phase locked loop) circuit, etc., and in this example, the reference clock 6fsc is six times the color subcarrier fsc.
and a double reference clock 2fsc is generated. The reference clock is controlled to always have a constant phase with respect to the horizontal synchronizing signal H.

The reference clock 2fsc is a deflection pulse generation circuit (42)
signals 6H and H/6, which are six times the horizontal synchronization signal H.
Signal switching pulse per r z y g z + b 1
1 r, x + g 21 ” 2 (Figure 3(b) B
) is getting a pulse. On the other hand, the reference clock 6fS
C is added to the sampling pulse generation circuit (34),
Here, the clock is delayed by one clock period by the shift register, and 1080
sampling pulses R1□.

G-engineer 1. B engineering □, RL2. G1□, B engineering 2. R2□, G
, 1. B21. R, □.

G,,,B,,~Rn,,Gn1. Bn1. Rn2. G
n2. Bn2 (Fig. 3(b) A) is generated sequentially,
After that, one transfer pulse t is generated. These sampling pulses R11 to Bn2 correspond to each picture element when one line of the video to be displayed is divided into 360 picture elements in the horizontal direction, and their positions are always constant with respect to the horizontal synchronizing signal H. controlled by.

These 1080 sampling pulses R, ~Bn2 are each 180 sets of sample hold circuits (31-1)
~(31-n), and as a result, each sample-and-hold circuit (31-1) to (31-n) has R of 2 pixels each when one line is divided into 180 pieces. □, G engineering, B□, R2, G2. Each B2 video signal is individually sampled and held. The sample held 180 sets of Rxr Glt B engineering, R2゜a2. After the B2 video signal is sampled and held for one line, it is stored in 180 sets of memories (32-1) to (
32-n), they are transferred all at once by a transfer pulse t, and are held here for the next horizontal period. This retained R
□.

G□, B1. The R, , G, , B2 signals are applied to switching circuits (35-1) to (35-n). The switching circuits (35-1) to (35-n) each have R,
, G1. B□.

It is composed of a tri-state or analog gate having individual input terminals for R2, az, and B2 and a common output terminal that sequentially switches and outputs them.

The output of each switching circuit (35-1) to (35-n) is 180 sets of pulse width modulation (PWM) circuit (37-1)
~(37-n), where the sample-held R1. G1. B1-R2-Gz* The reference pulse signal is pulse width modulated and output according to the magnitude of the B2 video signal.The repetition period of the reference pulse signal is the above signal switching pulse rx+g□,b, r2゜gz
It is desirable that the pulse width U) is sufficiently smaller than the pulse width of rbz, and for example, one having a ratio 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) to the control electrodes (5) of the display element.
(15-n) respectively. Each of the switching circuits (35-1) to (35-n) receives switching signals (rxr gzr bxe rz+ gzr bz) applied from the switching pulse generating circuit (36).
Simultaneous number switching is controlled by . The switching pulse generation circuit (36) is the same as the aforementioned deflection pulse generation circuit (42).
) Signal switching pulse from r□* glt b1+ r
Each horizontal period is divided into 6 and a switching circuit (35-
1) to (35-n), R1, G□, B work, R,
, G2. Each video signal of B2 is divided into one time period and outputted sequentially, and the pulse width modulation circuits (37-1) to (37-n
) so that the switching signal is supplied to r, 2g, and b□.

Generate rz+gzr bz.

What should be noted here is that the switching circuit (35-1
) to (35-n) R1. G1. B1. R
2°G2. B2 video signal supply switching and electron beam R, , G1 . B1.
The irradiation switching horizontal deflection of R2°G, , B, and the phosphor is controlled in synchronization so that they completely match both in timing and order. As a result, when the electron beam is irradiating the R1 phosphor, the irradiation amount of the electron beam is controlled by the R1 video signal, and G, B, lR2, G, , B are similarly controlled, and each Picture element R work G l + B 11R2,
G2. B2 The light emission of each phosphor is the R and G□ of that picture element.

B,,R2,G2. Each picture element is controlled by the B2 video signal, and each picture element is displayed by emitting light according to the input video signal. This control is for one line.
This is done simultaneously for 80 sets (2 picture elements each) to display an image of 360 pixels per line, and then sequentially for 240H lines starting from the upper line, so that one image is displayed on the screen (9). It will be displayed.

and one or more such operations are performed on one or more of the input television signals.
The result is repeated for each field.

Similar to a normal television receiver, the screen IJ-n (9
) The video television image is projected on top of the screen.

By the way, when an image display device (such as one or more) is used, the shape of the beam spot emitted by the electron beam deflected by the device for 16 lines vertically on the screen (9) is strictly speaking 16. The position of each line is different. This beam spot shape changes depending on the center voltage v4 of the vertical deflection signal, but as shown in FIG. I can't stop the focus around the 16th line, and there is one side in the vertical direction.
The beam spot shape is as if a narrow tail is drawn on both sides, and this force 1 is perceived as a difference in brightness between the two sides.

In order to solve this problem, the conventional number, Middle I1. ．． voltage v
Although attempts have been made to make the beam spot shapes of all lines uniform by setting 4 to different values for each line, it has been difficult to make the shapes exactly uniform, and it has not been possible to eliminate the brightness difference.

Note that FIG. 9 is a configuration diagram of the D-A converter (39), and (43
) is the D-A conversion section, (44) is the deflection processing section, (45)
is the amplification section.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and an object of the present invention is to provide an image display device that can obtain a uniform beam spot shape over the entire screen.

Structure of the Invention In order to achieve the above object, an image display device of the present invention comprises:
A screen having a plurality of line cathode electron beam generation sources, a phosphor that emits light when irradiated with the electron beams generated by the line cathode electron beam generation sources, a focusing electrode that focuses the electron beams, and an electrostatic deflection electrode that deflects the beam up to the screen;
a control electrode that controls the amount of the electron beam irradiated onto the screen to control the emission intensity; and a deflection means that uses an alternating current signal to minutely deflect the landing position of the electron beam on the screen about a steady position. The configuration is equipped with the following.

According to this configuration, by modulating the vertical deflection signal with an alternating current signal, etc., the landing position of the electron beam on the screen is slightly changed around the steady position, so that the ideal beam spot shape can be maintained. It is possible to change the visual beam spot diameter in the vertical direction without changing the position, and therefore, it is possible to obtain a uniform beam spot shape over the entire screen.

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

FIG. 10 shows D of an image display device in an embodiment of the present invention.
-A converter configuration diagram, this D-A converter (46) is connected to the D-A converter 1 (39) shown in FIG. Modulation section (49)
, it is a configuration with added. High frequency oscillator (47)
The ideal waveform to be generated is a triangular wave, and this triangular wave modulates the vertical deflection signal υ6 from the deflection processing section (44), while the phase shifting section (48) uses a triangular wave whose phase is shifted by 180° to generate a vertical deflection signal υ6. Deflection signal ν. ′ is modulated. In addition, D-A
The configuration other than the converter (46) is the same as that of the conventional example.

By doing this, the spot position of the electron beam on the screen (9) changes up and down from the steady state position in each line according to the amplitude of the triangular wave, and because the speed of change is fast, it is visually This is equivalent to constantly increasing the diameter of the beam spot in the vertical direction.

For example, as shown in Fig. 11, when focusing the raster beam for 16 lines in one vertical section using the conventional method, no trailing phenomenon occurs near the 1st line at the top end and near the 16th line at the bottom end. The amplitude of the modulating triangular wave is greatest near the 8th line, and gradually decreases toward the 1st line and the 16th line. If set to , the beam spot maintains its ideal shape without trailing, etc., and only the vertical shading appears to have changed, eliminating differences in beam spot shape between rasters.

As described in detail, according to the present invention, the landing position of the electron beam on the screen is slightly changed using a high-frequency signal, so the visual spot diameter can be changed while maintaining the ideal beam spot shape. can be changed, and a uniform beam spot shape can be obtained over the entire screen.

[Brief explanation of drawings]

FIG. 1 is an electrode configuration diagram of a conventional image display device, FIG. 2 is a diagram showing the smallest picture element on a screen, and FIG. 3 is a block diagram of a drive circuit and waveform diagrams of various parts. Figure 4 is a relationship diagram between vertical deflection signals and synchronization signals, Figure 5 is a timing chart of the counter, Figure 6 is a relationship diagram of drive output pulses, Figure 7 is a relationship diagram between horizontal deflection signals and synchronization signals, Figure 8 is an explanatory diagram of the beam spot shape on the fluorescent screen.
FIG. 9 is a block diagram of a D-A converter, and FIG. 1O is a block diagram of a D-A converter of an image display device in an embodiment of the present invention.
FIG. 11 is an explanatory diagram of changes in the vertical orientation of the beam on the phosphor screen of the image display device and the waveform of the vertical deflection signal. (1) ... Back electrode, (2) (2a) - (20)
... Line cathode, (3) (3') ... Honest focusing electrode, (4
) Vertical deflection electrode, (5) Beam flow control electrode, (7) Horizontal deflection electrode, (9) Screen, (20) Phosphor, (46) ... D-A converter, (47) ... High frequency oscillation section, (48) ... Phase shift section, (49) ... Modulation section agent Yoshihiro Morimoto Figure 2 Figure 3 (b A B Q D Fig. 4-11 1-] I 1 l L-" (b) ε' Sagi-nyo a'Ph"mu
3 S 1θ Figure a 1st/Figure

Claims (1)

[Claims] 1. A screen having a plurality of line cathode electron beam generation sources, a phosphor that emits light when irradiated with the electron beams generated by these line cathode electron beam generation sources, and a focusing electrode that focuses the electron beams; an electrostatic deflection electrode that deflects the electron beam up to the screen; a control electrode that controls the amount of the electron beam irradiated onto the screen to control the emission intensity; and deflection means for minutely deflecting the landing position of the electron beam about the steady position using an alternating current signal.