JPH069380B2 - Image display device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to generate an electron beam for each section when a screen on a screen is divided into a plurality of sections in the vertical direction, and to generate an electron beam for each section. The present invention relates to a device for deflecting a beam in a vertical direction to display a plurality of lines and displaying a television image as a whole.

2. Description of the Related Art Conventionally, a cathode ray tube has been mainly used as a display element for displaying a color television image, but the conventional cathode ray tube has a very long depth compared to the size of the screen, and a thin television receiver. Was impossible to create. In addition, although EL display elements, plasma display devices, liquid crystal display elements, etc. have been recently developed as flat plate display elements, none of them are sufficient in terms of performance such as brightness, contrast and color display, and are put to practical use. Has not reached the end.

Therefore, for the purpose of achieving a flat-panel display device by using an electron beam, an electron beam is generated for each section when the screen on the screen is divided into a plurality of sections in the vertical direction, and each section is generated. There is one in which each electron beam is deflected in the vertical direction to display a plurality of lines and a television image is displayed as a whole.

First, a basic configuration of the image display device used here will be described with reference to FIG. This display element includes a back electrode (1), a line cathode (2) as a beam source, vertical focusing electrodes (3) and (3 '), a vertical deflection electrode (4), and a beam flow control in order from the rear to the front. Electrode (5), horizontal focusing electrode (6), horizontal deflection electrode
(7), a beam accelerating electrode (8) and a screen (9) are arranged and housed, and these are housed in a vacuumed inside of a flat glass bulb (not shown). The wire cathode (2) as a beam source is stretched horizontally so as to generate an electron beam that is linearly distributed horizontally.
A plurality of such line cathodes (2) are provided in the vertical direction at appropriate intervals (in this case, only four of (2a) to (2d) are shown). In this example, 15 are provided. Let these be (2a) to (2o). These wire cathodes (2) are, for example, 10
The surface of a tungsten wire of ˜20 μφ is coated with an oxide cathode material for thermionic emission. And, these line cathodes (2a) ~ (2o) is heated so that a thermoelectron beam can be generated by passing an electric current, and as described later, from the above line cathode (2a) for a certain period of time. The electron beam is controlled to be emitted one by one. The back electrode (1) suppresses the generation of electron beams from other line cathodes other than the line cathode that is controlled to emit the electron beam for a certain period of time, and directs the generated electron beam only in the forward direction. And push it out. This back electrode (1) may be formed by a coating film of a conductive material attached to the inner surface of the rear wall of the glass bulb. Further, a 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 horizontally long slits (10) facing each of the line cathodes (2a) to (2o), and the electron beam emitted from the line cathode (2). Is taken out through the slit (10) and vertically focused. An electron beam for one horizontal line (360 pixels) is taken out at the same time. In the figure, only one horizontal section is shown. The slits (10) may be provided with crosspieces at appropriate intervals in the middle, or may be a row of through-holes arranged side by side at a small horizontal interval (an interval at which they are almost in contact with each other). May be configured as. The vertical focusing electrode (3 ') is also the same.

A plurality of vertical deflection electrodes (4) are arranged horizontally in the middle of each of the slits (10), and conductors (13) and (13) are provided on the upper and lower surfaces of the insulating substrate (12), respectively. ′) Is provided. Then, a vertical deflection voltage is applied between the conductors (13) and (13 ') facing each other to deflect the electron beam in the vertical direction. In this example, a pair of conductors (13) and (13 ') deflects the electron beam from one line cathode (2) vertically to a position for 16 lines. And
The 16 vertical deflection electrodes (4) form 15 pairs of conductors corresponding to each of the 15 line cathodes (2), and eventually 240 horizontal lines are drawn on the screen (9). Deflect the electron beam.

Next, the control device (5) is composed of a conductive plate (15) each having a slit (14) which is long in the vertical direction, and a plurality of the control devices (5) are arranged side by side in the horizontal direction at predetermined intervals. In this example
180 conductive plates (15-1) to (15-n) for control electrodes are provided. (Only 9 are shown in the figure). This control electrode
In (5), each electron beam is divided into two picture elements in the horizontal direction and taken out, and the passing amount thereof is controlled according to a video signal for displaying each picture element. Therefore,
If 180 conductive plates (15-1) to (15-n) for the control electrode (5) are provided, 360 picture elements can be displayed per horizontal line. Also, in order to display the image in color, each picture element has R, G,
It is supposed to display by the phosphor of three colors of B, and each control electrode (5)
, R, G, and B video signals corresponding to two picture elements are sequentially added. In addition, 180 control electrodes (5) conductive plate (15-1) ~ (15-n)
The video signals of 180 sets (2 picture elements per set) for one line are simultaneously applied to each of the above, 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 (180) slits (16) facing the slit (14) of the control electrode (5), and is horizontally The divided electron beams of each picture element are focused in the horizontal direction to form a narrow electron beam.

The horizontal deflection electrodes (7) are provided on a plurality of conductive plates (18) (1
8 '), each electrode (18) (18') 6
A horizontal deflection voltage is applied in stages to deflect the electron beam for each picture element in the horizontal direction, and the two sets of R, G, B phosphors are sequentially irradiated on the screen (9) to emit light. I will let you. The deflection range is the width of two picture elements for each electron beam in this embodiment.

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

The screen (9) is constructed by coating the back surface of the 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) is a phosphor of three colors of R, G, B for one slit (14) of the control electrode (5), that is, for each electron beam divided in the horizontal direction. Are provided in pairs of two, and are applied in stripes in the vertical direction. In FIG. 6, the broken lines drawn on the screen (9) indicate the vertical divisions corresponding to the plurality of line cathodes (2), and the two-dot chain line indicates the plurality of control electrodes (5). ) Indicates the division in the horizontal direction that is displayed corresponding to each.
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 and 16 lines in the vertical direction. It has a width of minutes. The size of one section is, for example, 1 mm in the horizontal direction and 10 mm in the vertical direction.

It should be noted that in FIG. 6, the length in the horizontal direction is greatly enlarged with respect to the vertical direction for the sake of clarity.

Further, 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, one electron beam. One or three or more picture elements may be provided, in which case R, G, B video signals for one or three or more picture elements are sequentially added to the control electrode (5), Horizontal deflection is performed in synchronization with it.

Next, the basic configuration of the drive circuit for displaying a television image on this display element and the waveforms of the respective parts will be described with reference to FIG. First, a drive portion for irradiating the screen (9) with an electron beam to cause the raster to emit 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. The back voltage (1) is -V ₁ , and the vertical focusing electrodes (3) (3 ') are Is V ₃ , V ₃ ′, V ₆ is for the horizontal focusing electrode (6), V ₈ is for the accelerating electrode (8), and the screen
A DC voltage of V ₉ is applied to (9).

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

The vertical deflection drive circuit (40) includes a vertical deflection counter (25), a vertical deflection signal storage memory (27), and a digital-analog converter (39) (hereinafter referred to as DA converter). As the input pulse of the vertical deflection drive circuit (40), the vertical synchronizing signal V and the 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 blanking period of the vertical cycle, and this count output is stored in the memory.
Supplied to address (27). The memory (27) outputs vertical deflection signal data (8 bits in this case) corresponding to each address, and the DA converter (39) outputs the vertical deflection signal data shown in FIG.
(b) Converted to the vertical deflection signals of υ and υ ′ shown in D).
This circuit has a memory address for storing a vertical deflection signal corresponding to each line of 240H, and 16 stages of vertical deflection signal can be obtained by storing the regulated data in the memory every 16H. it can.

On the other hand, the line cathode drive circuit (26) uses the vertical synchronizing signal V and the output of the vertical deflection counter (25) to drive the line cathode drive pulses a to o.
To create. FIG. 10 (a) shows the relationship between the vertical synchronizing signal V, the horizontal synchronizing signal H, and the lower 5 bits of the vertical deflection counter (25). FIG. 10 (b) shows a method for producing the line cathode drive pulses a'to o'for each 16H by using these signals. First
In FIG. 10, LSB indicates the lowest bit, and (LSB + 1) means a bit one higher than the LSB.

The first line cathode drive pulse a'is RS by using the vertical synchronizing signal V and the output (LSB + 4) of the vertical deflection counter (25).
It can be created by a flip-flop or the like, and the line cathode drive pulses b ′ to o ′ are output from the vertical deflection counter (25) (LS) by using a shift register to output the line cathode drive pulse a ′.
It can be obtained by transferring the inverted version of B + 3) as a clock. The driving pulse a'-o 'is inverted to a low electric potential only during each pulse period, and is set to a high electric potential of about 20 V in the other periods.
It is converted to o (Fig. 8 (b) E) and added to each of the line cathodes (2a) to (2o).

Each of the line cathodes (2a) to (2o) is heated by being supplied with an electric current during the high potential of the drive pulses a to o.
The heating state is maintained so that electrons can be emitted during the low potential period of. As a result, electrons are emitted from the 15 line cathodes (2a) to (2o) only during the 16H period in which the low-potential drive pulses a to o are applied. During the period when the high potential is applied, the potential of the line cathode (2a) is higher than the potential at the position of the line cathode (2) defined by the bias voltage applied to the back electrode (1) and the vertical focusing electrode (3). No electrons are emitted from the line cathodes (2a) to (2o) because the high potential applied to () to (2o) becomes more positive. Thus, in the line cathode (2), during the effective vertical scanning period, electrons are sequentially emitted from the upper line cathode (2a) toward the lower line cathode (2o) for 16H periods. 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 vertically focused to form a flat electron beam. .

Next, the linear cathode drive pulses a to o and the vertical deflection signals υ and υ '
The relationship with and will be described with reference to FIG. Fig. 11
(a) is a waveform diagram of a linear cathode drive pulse, (b) is a waveform diagram of a vertical deflection signal, and (c) is a waveform diagram of a horizontal deflection signal. Fig. 11 (b)
The vertical deflection signals .upsilon., .Upsilon. 'Of .vertline. Are changed by 1H for 16H periods of the respective line cathode pulses a to o in FIG. The center voltage of both the vertical deflection signals υ and υ ′ is V
_In the case of No. ₄ , υ gradually increases, and ν ′ gradually decreases, so that they change in opposite directions.
These vertical deflection signals υ and υ'are respectively the vertical deflection electrodes.
The electron beams generated from the respective line cathodes (2a) to (2o), which are applied to the electrodes (13) and (13 ') of (4), are vertically deflected in 16 steps, as described above. Screen
(9) Above, one electron beam is deflected so that a raster for 16 lines is sequentially drawn from the top one line at a time.

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), and each electron beam is one line from the top to the bottom in 15 vertical sections. By deflecting each minute, the electron beam is vertically deflected by one line sequentially from the first line at the upper end to the 240th line at the lower end on the screen (9), and a raster of a total of 240 lines is drawn.

The electron beam vertically deflected in this way is divided into 180 sections in the horizontal direction by the control electrode (5) and the horizontal focusing electrode (6) and is extracted. FIG. 7 shows one of them. The passing amount of this electron beam is controlled by the control electrode (5) for each section, and is horizontally focused by the horizontal focusing electrode (6) to form one thin electron beam, which is horizontally moved by the horizontal deflecting means described below. Is deflected in 6 steps in the direction, and R, G, B of two picture elements on the screen (9)
Each phosphor (20) is sequentially irradiated. FIG. 7 shows vertical and horizontal divisions. Each of the control electrodes (5) (15-
The phosphors corresponding to 1) to (15-n) 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 ₂ and G. ₂ and B ₂ .

Next, the horizontal deflection drive circuit (41) is a horizontal deflection counter.
(28) (11 bits), memory that stores the horizontal deflection signal
(29) and a DA converter (38). The input pulse of the horizontal deflection driving circuit (41) is synchronized with the vertical synchronizing signal V and the horizontal synchronizing signal H as shown in FIG. 12, and a pulse 6H having a repetition frequency of 6 times the horizontal synchronizing signal H is used. The horizontal deflection counter (28) is reset by the vertical synchronizing signal V and counts horizontal 6 times pulse 6H. This horizontal deflection counter (28) has 6 times during 1H and 240H × during 1V.
6 / H = 1440 counts, this count output is a memory
Supplied to address (29). Horizontal deflection signal data from the memory (29) according to the address (8 bits here)
Is output, and the D-A converter (38) outputs the signal shown in FIG.
It is converted into horizontal deflection signals such as h and h'shown in C). This circuit has a memory address for storing the horizontal deflection signal corresponding to each of 6 × 240 lines, and by storing 6 pieces of regular data for each line in the memory, a 6-step wave is generated in the 1H period. Can be obtained.

The horizontal deflection signal is 'a, both of central voltage is V _7, h is sequentially decreased, h' a pair of horizontal deflection signals h and h that varies six stages as shown in FIG. 12 sequentially increases As they do, they change in opposite directions. These horizontal deflection signals h and h'are respectively supplied to the electrodes (18) of the horizontal deflection electrode (7).
Added to (18 '). As a result, the electron beams divided in the horizontal direction are R, G, B, R, G, B (R ₁ , G ₁ , B ₁ , R ₂ , G ₂ of the screen 9 during each horizontal period. ，
The phosphor of B ₂ ) is horizontally deflected so as to be sequentially irradiated for H / 6 periods. Thus, in the raster of each line, the electron beam is R ₁ , R ₁ for each of the 180 horizontal sections.
The phosphors (20) of G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ are sequentially irradiated.

Therefore, an electron beam R ₁ ,
A color television image on the screen (9) can be displayed by modulating with the video signals of G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ .

Next, the modulation control part of the electron beam will be described. First, the composite video signal applied to the television signal input terminal (23) is applied to the color demodulation circuit (30), where R
-Y and BY color difference signals are demodulated, G-Y color difference signals are matrix-synthesized, and they are further combined with the luminance signal Y to obtain R, G, B primary color signals (hereinafter R, G). , B video signal) is output. The R, G and B video signals are applied to 180 sets of sample hold circuits (31-1) to (31-n). Each of the sample-hold circuits (31-1) to (31-n) has six sample-hold circuits for R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ . ing. These sample and hold outputs are stored in holding memories (32-1) to (32-
n).

On the other hand, the reference clock oscillator (33) is composed of a PLL (phase locked loop) circuit or the like, and in this example, generates a reference clock 6sc which is 6 times the color subcarrier sc and a reference clock 2sc which is 2 times the color subcarrier sc. The reference clock is controlled so as to always have a constant phase with respect to the horizontal synchronizing signal H. The reference clock 2sc is applied to the deflection pulse generation circuit (42), and the signal 6H which is 6 times the horizontal synchronizing signal H and the signal switching pulses r ₁ , g ₁ , b ₁ , r ₂ , for each H / 6,
The pulses g ₂ and b ₂ (FIG. 8 (b) B) are obtained. On the other hand, the reference clock 6sc is applied to the sampling pulse generation circuit (34), where it is delayed by one clock cycle by the shift register, etc., so that the effective horizontal scanning period (about 50 μsec) of the horizontal period (63.5 μsec). 1080 sampling pulses R ₁₁ , G ₁₁ , B ₁₁ , R ₁₂ , G ₁₂ , B between
₁₂ , R ₂₁ , G ₂₁ , B ₂₁ , R ₂₂ , G ₂₂ , B _{22 to} Rn ₁ , G
n ₁ , Bn ₁ , Rn ₂ , Gn ₂ , and Bn ₂ (FIG. 8 (b) A) are sequentially generated, and then one transfer pulse t is generated. The sampling pulses R _{11 to} Bn ₂ correspond to respective picture elements when one line of the image to be displayed is divided into 360 picture elements in the horizontal direction, and the position thereof is the horizontal synchronization signal H.
Is controlled so that it is always constant.

Each of the 1080 sampling pulses R _{11 to} Bn ₂ is added to each of the 180 sets of sample hold circuits (31-1) to (31-n) by six, and thereby each sample hold circuit (3
In 1-1) to (31-n), each video signal of R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ of each two picture elements when one line is divided into 180 pieces. Are sampled and held individually. The 180 sampled and held R ₁ , G ₁ , B ₁ ,
The video signals of R ₂ , G ₂ and B ₂ are simultaneously transferred by a transfer pulse t to 180 sets of memories (32-1) to (32-n) after the sample and hold for one line is completed, and the next one Hold for the horizontal period. This retained R ₁ , G ₁ , B ₁ , R ₂ , G
The signals ₂ and B ₂ are applied to the switching circuits (35-1) to (35-n). Each of the switching circuits (35-1) to (35-n) has an individual input terminal of R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , B ₂ and a common output terminal for sequentially switching and outputting them. It has a tri-state or an analog gate.

The output of each switching circuit (35-1) ~ (35-n) is added to 180 sets of pulse width modulation (PWM) circuits (37-1) ~ (37-n),
Here, the sample-held R ₁ , G ₁ , B ₁ , R ₂ ,
The reference pulse signal is pulse-width modulated and output according to the magnitudes of the G ₂ and B ₂ video signals. The repetition cycle of the reference pulse signal is the signal switching pulses r ₁ , g ₁ , b ₁ ,
It is desirable that the pulse width is sufficiently smaller than the pulse widths of r ₂ , g ₂ and b ₂ , and for example, a pulse width of about 1:10 to 1: 100 is used.

The output of this pulse width modulation circuit (37-1) to (37-n) is used as a control signal for modulating the electron beam and is used as a control electrode of the display element.
It is added individually to the 180 conductive plates (15-1) to (15-n) of (5). The switching circuits (35-1) to (35-n) are simultaneously switched and controlled by the switching pulses r ₁ , g ₁ , b ₁ , r ₂ , g ₂ , b ₂ applied from the switching pulse generation circuit (36). . The switching pulse generation circuit (36) is controlled by the signal switching pulses r ₁ , g ₁ , b ₁ , r ₂ , g ₂ , b ₂ from the deflection pulse generation circuit (42) described above, and each horizontal period is Dividing into 6 and switching the switching circuits (35-1) to (35-n) by H / 6, R ₁ , G ₁ , B ₁ , R ₂ ,
A switching signal r is supplied so that each of the G ₂ and B ₂ video signals is time-divided and sequentially output and supplied to the pulse width modulation circuits (37-1) to (37-n).
₁ , ₁ , g ₁ , b ₁ , r ₂ , g ₂ , b ₂ are generated.

Note that the switching circuits (35-1) to (3
5-n) switching of supply of video signals of R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , B ₂ and electron beams R ₁ , G ₁ , B ₁ , R by the horizontal deflection drive circuit (41). _It means that the irradiation switching horizontal deflection of ₂ , G ₂ and B ₂ phosphors is synchronously controlled so as to be completely coincident in both timing and sequence.
As a result, when the R ₁ phosphor is irradiated with the electron beam, the irradiation amount of the electron beam is controlled by the R ₁ image signal, and the G ₁ , B ₁ , R ₂ , G ₂ , and B ₂ are similarly controlled. R ₁ , G ₁ , B ₁ , R ₂ , G ₂ , B _{2 of} each picture element
The luminescence of each phosphor is R ₁ , G ₁ , B ₁ , R ₂ ,
It is controlled by the video signals of G ₂ and B ₂ , respectively, and each picture element is luminescently displayed according to the input video signal. This control is simultaneously performed for 180 pairs of one line (two pixel elements each), 360-pixel image of one line is displayed, and further 240 H lines are sequentially performed from the upper line, and the screen (9 ) One image above will be displayed.

Then, the above-described operation is 1 of the input television signal.
This is repeated for each field, and as a result, a moving image of television image is displayed on the screen (9) like a normal television receiver.

The landing position of the electron beam is detected by a resistor or a triangular hole on the focusing electrode. In this detection method, in the vertical blanking period, the light is deflected so as to emit light at an appropriate time interval (for example, one field) at the upper and lower ends of one section Kn in the vertical direction, and the landing position in each case is detected by a current value. Then, this current value is converted into a voltage value, and the amount of change in amplitude and offset is obtained by arithmetic processing. Using this, the deflection waveform is changed to return the landing position to the normal position (Japanese Patent Application No. 59 -211811 and Japanese Patent Application No. 59-265713
issue).

Problems to be Solved by the Invention In the conventional vertical landing position temporal compensation system, since the amplitude and the offset change amount are detected during the vertical blanking period, it takes a long time (for example, one frame) to detect the timing of the detection and feedback. Causes a large time lag, which causes the following problems.

(1) A memory is required to store the detected value.

(2) Deflection data for obtaining a special deflection is necessary.

(3) Complex timing pulses are required to operate the system.

The present invention solves the above problems, and an object of the present invention is to provide an image display device that gives feedback in real time.

Means for Solving the Problems To solve the above problems, the present invention provides a plurality of linear cathode electron beam sources, a screen having a phosphor that emits light when irradiated with the electron beams, and A focusing electrode for focusing the electron beam generated by the electron beam generation source, an electrostatic deflection electrode for deflecting the electron beam until reaching the screen, and an amount of irradiating the screen with the electron beam are set. An image display device having a control electrode for controlling the emission intensity and an analog sensor for detecting a vertical landing (deflection) position are provided, and a detection signal and a vertical deflection signal obtained by calculating the output of the analog sensor and converting the voltage are calculated. An analog comparator is provided to compare the signal and the signal that corresponds to the landing position deviation obtained from this analog comparator. A feedback loop is provided in the vertical deflection circuit by means of superimposing it on the vertical deflection signal.

With this configuration, the signal waveform detected by, for example, the resistor or the triangular hole provided in the focusing electrode during the image display period is calculated, and an appropriate function is applied to adjust the amount of offset, gain, etc.,
A signal corresponding to the landing position deviation is obtained by comparing this with the signal (υ−υ ′) / 2 obtained by calculating from the vertical deflection signals υ and υ ′, and this signal is obtained in real time from the vertical deflection signal υ,
Feedback is made to υ ′ to perform a shift to perform stable compensation of the vertical landing position. In this way, feedback is given in real time, so no memory is required, and
It does not require special deflection data or complex control pulses to operate the system.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a feedback system for compensating for the deviation of the vertical landing position of the electron beam of the image display device in one embodiment of the present invention. In Fig. 1, (2
7) is a memory for storing the signal from the vertical deflection counter (25) of the image display device, and (39) is a DA converter, which is the same as that shown in FIG. (51) is a vertical deflection signal output circuit, (52) is a D / A converter 39 D / A converter for vertical deflection signals.
Vertical output signals from A (c) (d) υ, υ'to (υ-υ ')
A calculator that produces a signal of / 2, (53) is a divider that produces a signal of (I ₁ -I ₂ ) / (I ₁ + I ₂ ) from the detection currents I ₁ and I ₂ of the sensor, and (54) is division A function generator for multiplying the output of (53) by an appropriate function f (x), (55) a comparator for comparing the outputs from the arithmetic unit (52) and the function generator (54), (56 )(Five
6) ′ is a DA converter (39) according to the output from the comparator (55).
Is a level shift circuit for controlling the output of the D / A (c) (d), and each output is an output section (c) of the output circuit (51).
Input in (d).

2 and 3 show an example of a landing position detecting sensor, and FIG. 2 shows a focusing electrode (see FIG. 6) of an image display device.
Triangle holes (61) and (62) are provided at both outer edges of the effective screen of (3) ′). Fig. 3 shows resistors at both outer edges of the effective screen.
(71) and (72) are shown. Triangle hole (61) (62)
In the case of, the left and right sides are formed so that the shapes are opposite to each other.
In this case, the left and right sides are arranged in a zigzag pattern, and the total number of left and right sides is n.

Fig. 4 shows resistors for landing position detection (71) (72)
Also, the positional relationship between the triangular holes (61) and (62) and the electron beam is shown, and FIGS. 5 (a) and (b) show a divider (53) from the detection currents I ₁ and I ₂ detected by the detection sensor. , Through a function generator (54). (81) and DA converter for vertical deflection signal (39)
From the output signals υ and υ ′ of
υ ′) / 2 signal (82) is shown.

The operation of the feedback system thus configured will be described below. As shown in FIG. 4, the electron beam is applied to the triangular holes (61) (62) or the resistors (71) (72) shown in FIG. From the arranged sensor, it is possible to obtain a current output according to the position where the electron beam is irradiated. That is, as the electron beams are irradiated to the upper portions of the resistors 71 and 72, the detection current I ₁ increases and the detection current I ₂ decreases. Similarly, the current I ₂ flowing into the triangular hole (62) increases,
The current I ₂ flowing into (62) decreases. In FIG. 1, I ₁ and I ₂ indicate the detected currents. Next, the calculation of I ₁ -I ₂ is performed to increase the sensitivity and reduce the noise, and the result of the difference is divided by (I ₁ + I ₂ ) to eliminate the detection error due to the change in the emission amount. This signal is multiplied by an appropriate function f (x) to adjust the amount of offset, gain and the like. If the electron beam is in the normal position, the function generator
The output signal (81) of (54) (Fig. 5 (a)) and the output signal (82) of the computing unit (52) (Fig. 5 (b)) match. If the n-th electron beam positioning position shown in FIG. 4 is displaced above the normal position, the comparator 55 outputs a positive signal corresponding to the displacement amount. Level shift circuit
(56) (56) 'receives this signal, and one level shift circuit (56) instantly works to lower the DC voltage V of the vertical deflection signal nth stage, and the level shift circuit (56)' DC voltage Work to raise V '. As a result, footback is applied until the n-th stage electron beam returns to the normal position, and the vertical landing position compensation of the electron beam can be performed in real time.

As described above, according to the present invention, the vertical landing position compensation of the electron beam can be performed in real time during the image display period. Therefore, the conventional memory is not required, and further, the special deflection is not required, and the complexity is further increased. It does not require any control pulse.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of an image display device according to an embodiment of the present invention, and FIGS. 2 and 3 are triangular holes and resistors provided as electron beam vertical landing position detection sensors on a focusing electrode. FIG. 4 is a diagram for explaining the relationship between the landing position and the sensor, FIG. 5 is a diagram showing a detection signal waveform and a deflection signal waveform, and FIG. 6 is an example used in the image display device of the present invention. An exploded perspective view of the image display device,
FIG. 7 is an enlarged view of a phosphor screen of the image display device, FIG. 8 is a block diagram and a waveform diagram showing a basic configuration of a drive circuit of the image display device, and FIG. 9 is an operation explanation of a vertical deflection drive circuit. Of FIG. 10, FIG. 10 is a waveform diagram for explaining the operation of the line cathode drive circuit, FIG. 11 is a waveform diagram of each drive signal, and FIG. 12 is a waveform diagram for explaining the operation of the horizontal deflection drive circuit. . (2) (2a) to (2o) …… line cathode, (3) (3 ′) …… vertical focusing electrode, (4) …… vertical deflection electrode, (5) …… beam flow control electrode,
(7) ... Horizontal deflection electrode, (9) ... Screen, (20) ... Phosphor, (27) ... Memory, (39) ... DA converter, (52) ...
… Calculator, (53) …… divider, (54) …… function generator, (5
5) …… Comparator, (56) (56) ′ …… Level shift circuit, (61)
(62) …… Triangle hole, (71), (72) …… Resistor

Claims (1)

[Claims] 1. A plurality of linear cathode electron beam generators, a screen having a phosphor that emits light when irradiated with the electron beams, and a focusing electrode that focuses the electron beams generated by the electron beam generators. And an electrostatic deflection electrode for deflecting the electron beam until reaching the screen, and an image display element having a control electrode for controlling the emission intensity by controlling the amount of irradiation of the screen with the electron beam. And an analog comparator for detecting a vertical landing (deflection) position, and providing an analog comparator for comparing the detection signal obtained by calculating the output of the analog sensor and converting the voltage with the signal obtained by calculating the vertical deflection signal. To the vertical deflection circuit by means of superimposing the signal corresponding to the landing position deviation obtained from the detector on the analog vertical deflection signal at that time. An image display device provided with I over-back loop.