JPS644715B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention vertically divides a screen into a plurality of sections, generates an electron beam for each section, and deflects each electron beam vertically for each section. This invention relates to a device for displaying a plurality of lines and displaying a television image as a whole, and the object is to provide a device that can easily and accurately perform vertical blanking operations on the screen. It is something.

Conventionally, cathode ray tubes have been mainly used as display elements for displaying color television images, but conventional cathode ray tubes have a very long depth compared to the screen size, making it difficult to create thin television receivers. It was impossible. 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 screen on the screen is vertically divided into multiple sections and an electron beam is generated for each section. A system was devised in which the electron beam was deflected vertically to display multiple lines, thus displaying a television image as a whole.

First, a basic configuration example of the image display element used here will be explained with reference to FIG.

This display element is arranged in order from the back to the front.
A back electrode 1, a line cathode 2 as a beam source, vertical focusing electrodes 3, 3', a vertical deflection electrode 4, a beam flow control electrode 5, a horizontal focusing electrode 6, a horizontal deflection electrode 7, a beam accelerating electrode 8 and a screen plate 9. They are housed within the evacuated interior of a flat glass bulb (not shown).

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 (here, 2-2-4
(Only books shown) provided. In this embodiment, it is assumed that 15 pieces are provided. Let's say 2i~2yo. These line cathodes 2 have a diameter of, for example, 10 to 20 μφ.
An oxide cathode material is coated on the surface of a tungsten wire. Then, as will be described later, the electron beams are controlled to be emitted sequentially from the upper line cathode 2a for a fixed period of time. Back electrode 1
has the effect of suppressing the generation of electron beams from other line cathodes 2 other than the line cathode 2 that is controlled to emit electron beams for a certain period of time, and pushing out the generated electron beams only in the forward direction. do. 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 2I to 2Y, and extracts the electron beam emitted from the line cathode 2 through the slit 10, and focus in a direction. 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 have been done. The vertical focusing electrode 3' is also similar.

A plurality of vertical deflection electrodes 4 are arranged horizontally in the middle of each of the slits 10, and are each composed of conductors 13 and 13' provided on the upper and lower surfaces of an insulating substrate 12. has been done. And the opposing conductors 13, 13'
A vertical deflection voltage is applied between them to deflect the electron beam in the vertical direction. In this embodiment, the electron beam from one line cathode 2 is vertically deflected to positions corresponding to 16 lines by a pair of conductors 13, 13'. And, by 16 vertical deflection electrodes 4, 15
Fifteen conductor pairs corresponding to each of the book line cathodes 2 are constructed, and the electron beam is ultimately deflected to draw 240 horizontal lines on the screen 9.

Next, the control electrodes 5 are composed of conductive plates 15 each having a vertically long slit 14, and a plurality of control electrodes 15 are arranged in parallel in the horizontal direction at predetermined intervals. In this embodiment, 320 conductive plates 15a to 15m for control electrodes are provided (only 10 are shown in the figure). Each of the control electrodes 5 separates and extracts the electron beam into one picture element 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 320 control electrodes 5 are provided, 320 picture elements can be displayed per horizontal line. In addition, in order to display images in color, each picture element is R, G,
It is assumed that display is performed using phosphors of three colors, B, and the R, G, and B video signals are sequentially applied to each control electrode 5. In addition, 320 sets of video signals for one line are simultaneously applied to the 320 control electrodes 5, and an image 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 (320 slits 16) opposite to the slits 14 of the control electrode 5. Each beam is focused horizontally into a narrow electron beam.

The horizontal deflection electrode 7 is composed of a plurality of conductive plates 18 arranged vertically in the middle of each of the slits 16, and a horizontal deflection voltage is applied between each conductive plate 18 for each picture element. The electron beams are respectively deflected in the horizontal direction, and the R, G, and B phosphors are sequentially irradiated on the screen 9 to cause them to emit light. In this embodiment, the deflection range is the width of one picture element 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 is arranged for each slit 14 of the control electrode 5, that is, for each horizontally divided electron beam.
A pair of phosphors in each of the three colors R, G, and B are provided, and are applied in stripes in the vertical direction. In FIG. 1, the broken lines drawn on the screen 9 indicate divisions in the vertical direction that are displayed corresponding to each of the plurality of line cathodes 2, and the two-dot chain lines correspond to each of the plurality of control electrodes 5. Indicates the horizontal division displayed. As shown in the enlarged view in Fig. 2, one section partitioned by these two has R, G, and B phosphors 20 for one pixel in the horizontal direction, and 16 lines in the vertical direction. It has a width of
For example, the size of one section is 1 in the horizontal direction.
mm, and the vertical direction is 16 mm.

Note that in FIG. 1, the length in the horizontal direction is greatly enlarged relative to the length in the vertical direction for clarity.

Further, in this embodiment, only one pair of R, G, and B phosphors 20 are provided for one picture element for one control electrode 5, that is, one electron beam, but two
Of course, two or more pairs for more than two picture elements may be provided, and in that case, R, G, and B video signals for two or more picture elements are sequentially applied to the control electrode 5.
Horizontal deflection is performed in synchronization with this.

Next, the basic configuration of a drive circuit for displaying television images on this display element will be explained with reference to FIG. First, a driving portion for irradiating the screen 9 with an electron beam to emit raster light will be 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 drive pulse generation circuit 25 is composed of a counter that is reset by a vertical pulse and counts horizontal pulses, and is configured to operate during an effective vertical scanning period (here, 240 hours) excluding the vertical retrace period of the vertical period. 15 driving pulses each having a length of 16H period are generated sequentially during each period (referred to as period). These drive pulses I, B...Y are applied to the line cathode drive circuit 26, where they are inverted and brought to a low potential only during each pulse period, and at approximately 200 mV during the remaining periods.
A line cathode drive pulse I′ made at a high potential of volts,
It is converted into B'...Yo', and each line cathode 2A, 2B,...
...Added to 2yo. Each line cathode 2a, ...2yo is heated by a current flowing through it during the high potential of the driving pulses I' to Y', and can emit electrons even during the low potential period of the driving pulses I' to Y'. The heated state is maintained. As a result, 15 wire cathodes 2-2
From y to y, low potential drive pulses are applied to each
Electrons are emitted only during the 16H period when yo′ is added. During the period when a high potential is applied, the potential at the line cathode 2 is lower 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 applied high potential becomes positive, the line cathodes 2-2
No electrons are emitted from yo. Thus, in the line cathode 2, during the effective vertical scanning period, from the upper line cathode 2A to the lower line cathode 2Y,
Electrons are emitted every 16H 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 to form a flat electron beam.

Next, the vertical deflection drive circuit 27 is composed of a counter that counts the horizontal synchronizing signal reset by each of the vertical drive pulses I to Y, a conversion circuit that D/A converts the count output, and the like. During the 16H period of each vertical drive pulse, a pair of vertical deflection signals v and v' are generated that change in 16 steps by 1H. The vertical deflection signals v and v′ both have a center voltage of V ₄ , and v increases sequentially,
v′ is configured to change in opposite directions so as to decrease sequentially. These vertical deflection signals v and v' are applied to electrodes 13 and 1 of the vertical deflection electrode 4, respectively.
3', so that each line cathode 2
The electron beam generated from I~2Yo is vertically
It is deflected in 16 steps, and as mentioned earlier, on the screen 9, one electron beam is deflected so that a raster of 16 lines is sequentially drawn one line at a time from the top.

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

The electron beam thus vertically deflected is horizontally deflected by 320 degrees by the control electrode 5 and the horizontal focusing electrode 6.
It is divided into sections and taken out. Figure 1 shows one of these categories. The amount of electron beam passing through each section is controlled by a control electrode 5, and horizontally focused by a horizontal focusing electrode 6 into a single narrow electron beam, which is then controlled by horizontal deflection means described below. The R, G, and B phosphors 2 on the screen 9 are deflected horizontally in three stages.
0 is sequentially irradiated.

That is, the horizontal drive pulse generation circuit 28 is composed of three cascade-connected monostable multivibrators, etc., and is triggered by a horizontal synchronization signal to generate three horizontal drives with equal pulse widths within one horizontal period. Generate pulses r, g, b. Here, as an example, each pulse width is approximately 17 μsec.
3 during the effective horizontal scanning period of 50μsec.
Three pulses r, g, and b are generated. These horizontal drive pulses r, g, and b are applied to the horizontal deflection drive circuit 29. The horizontal deflection drive circuit 29 generates a pair of horizontal deflection signals h and h' that change in three stages by being switched by the horizontal drive pulses r, g, and b. Both horizontal deflection signals h and h' have a center voltage of V ₇ , and h increases sequentially,
h' change in opposite directions so that they decrease sequentially. 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 horizontally deflected so as to sequentially irradiate the R, G, and B phosphors of the screen 9 for 17 μsec during each horizontal period. However, in the display element of FIG. 1, one conductive plate 18 or 18' is used in the horizontal deflection electrode 7.
is used to deflect the electron beams of two adjacent sections, and is designed to produce a deflection effect on the adjacent electron beams in mutually opposite directions, so the electron beam of the 320 sections is If a number of sections are deflected in the order of R→G→B, then an even number of sections is deflected in the order of B→G→R.
It is deflected in the opposite direction every other section, such that it is deflected in the order of .

Thus, in each line raster, the electron beam is divided into R, G,
Each phosphor 20 of B is sequentially irradiated.

Therefore, a color television image can be displayed on the screen 9 by modulating the electron beam with R, G, and B video signals for each horizontal section of each line.

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 color difference signals of R-Y and B-Y are demodulated,
The G-Y color difference signals are matrix-synthesized, and further, they are combined with the luminance signal Y to generate R, G,
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 320 sample and hold circuit sets 31a to 320.
31n. Each sample and hold circuit group 31a to 31n has three circuits for R, G, and B.
It has several sample and hold circuits. The sample and hold outputs of these sample and hold circuit sets 31a to 31n are each held by a memory set 32a.
~32n.

On the other hand, the sampling reference clock oscillator 33
is composed of a PLL (phase locked loop) circuit, etc., and generates a reference clock of approximately 6.4 MHz in this embodiment. This reference clock is controlled so that it always has a constant phase with respect to the horizontal synchronizing signal H. This reference clock is applied to the sampling pulse generation circuit 34, where it is delayed by one clock cycle by a shift register, etc., so that the reference clock is applied to the sampling pulse generating circuit 34, where it is delayed by one clock period by a shift register, etc. Sampling pulses a to n are sequentially generated, and then one transfer pulse is generated. These sampling pulses a to n correspond to each picture element when one line of the video to be displayed is divided horizontally into 320 picture elements, and their positions are always constant with respect to the horizontal synchronization signal H. controlled by.

These 320 sampling pulses a to n correspond to the above 320 sample and hold circuit sets 31.
a to 31n, thereby providing one line to each sample and hold circuit set 31a to 32n.
When divided into 320 picture elements, the R, G, and B video signals of each picture element are individually sampled and held. The sampled and held 320 sets of R, G, and B video signals are stored in 320 sets of memories 32a to 32a after completion of sample and hold for one line.
32c by a transfer pulse t,
Here, it is held for the next one horizontal period.

The R, G, and B video signals for one line held in the memories 32a to 32n are respectively applied to 320 pulse width modulation circuit sets 37a to 37n, where the sampled and held R, G, and B video signals are The reference pulse signal is pulse width modulated according to the magnitude of the pulse width and is output. It is desirable that the repetition period of the reference pulse signal is sufficiently smaller than the pulse width of the horizontal drive pulses r, g, and b in the horizontal deflection circuit, for example, from 1:10 to
A ratio of about 1:100 is used.

The output signals of the pulse width modulation circuit sets 37a to 37n are sent to switching circuits 35a to 35, respectively.
added to n. Switching circuits 35a to 35
Each of the switching circuits 35a to 35n has individual input terminals for R, G, and B and a common output terminal that sequentially switches and outputs them, and the output of each switching circuit 35a to 35n is displayed as a control signal for modulating the electron beam. 320 conductive plates 15a of the control electrode 5 of the element
~15n each separately. Each of the switching circuits 35a to 35n is simultaneously switched and controlled by a switching pulse applied from a switching pulse generating circuit 36. The switching pulse generation circuit 36 is controlled by the pulses r, g, and b from the horizontal driving pulse generation circuit 28 described above, and the switching circuit divides approximately 50 μsec at the center of each horizontal period into three parts and generates approximately 17 μsec each. 35a-3
5n, the R, G, and B video signals are time-divided and output alternately and sequentially to the control electrodes 15a to 15n.
Switching signals r, g, and b are generated so as to be supplied to the input terminals. However, among the switching circuits 35a to 35n, odd numbered switching circuits 35a and 3
5c... is switched in the order of R→G→B, and even-numbered switching circuits 35b, 35d...35
Conversely, n is switched in the order of B→G→R.

What should be noted here is that the switching circuit 3
The switching of the supply of R, G, and B video signals in 5a to 35n and the horizontal deflection of the horizontal deflection of the irradiation of the electron beams R, G, and B to the phosphor by the horizontal deflection drive circuit 29 are completely performed in both timing and order. It is synchronously controlled to match. As a result, when the electron beam is irradiating the R phosphor, the irradiation amount of the electron beam is controlled by the R video signal, and G and B are similarly controlled, so that the R and G of each picture element are controlled in the same manner. , B phosphors are controlled by the R, G, and B video signals of the picture elements, and each picture element is displayed by emitting light in accordance with the input video signal. Such control is performed simultaneously on 320 picture elements for one line to display one line of video, and then sequentially performed on 240-minute lines starting from the upper line, so that one video is displayed on screen 9. That will happen.

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.

As described above, television images are projected on this display device, but in order to accurately display images in this device, it is necessary to use multiple electron beam sources, for example, a line cathode, to generate electrons. The drive for generating the beam is well synchronized with the television signal, and
It is necessary to prevent the electron beam from being generated when the blanking period is unnecessary.

An object of the present invention is to provide an apparatus that can accurately and easily control the drive of such an electron beam generation source.

Hereinafter, one embodiment will be described in detail with reference to FIGS. 4 and 5.

FIG. 4 shows a specific example of the configuration of the vertical drive pulse generation circuit 25 and the line cathode drive circuit 26, and FIG. 6 shows waveforms of each part thereof. Vertical drive pulse generation circuit 25
First, a counter/decoder 38 for generating vertical drive pulses is provided. This counter/decoder 38 counts horizontal pulses such as a horizontal synchronizing signal, and sequentially inputs and outputs 16H width drive pulses every 16H period...
…It is something that causes yo.

In order to control the drive pulse generation in the counter decoder 38, the monostable multivibrator 39 is triggered by the vertical synchronization signal V obtained from the synchronization separation circuit to create a pulse Vd up to just before the effective vertical scanning period. The trailing edge sets flip-flop 40 to terminate the vertical blanking pulse VBL. flipflop 4
The vertical blanking pulse VBL with an output of 0 is applied to the counter decoder 38 as a reset signal, and the counter decoder 38 receives this pulse.
Count and decode operations are performed only when VBL is high. Therefore, by controlling the pulse VBL as described above, the counter decoder 38 can always start operating from the start of the effective vertical scanning period, and the vertical drive pulses I to Y can be output from its output terminals I to Y. can be generated. The trailing edge of the last drive pulse then resets the flip-flop 40 to bring the pulse VBL to a low level so that no output is generated from the counter decoder 38 until the beginning of the next valid vertical scan period. .

Thus, with this circuit, it is possible to always accurately generate drive pulses y-y in synchronization with the vertical synchronization signal.

The drive pulses I to Y created in this manner are applied to the bases of the transistors 41A to 41Y of the line cathode drive circuit 26, respectively, and are rendered conductive only during the pulse period. This transistor 41i~4
The collectors of 1 and 1 are connected to the positive power supply +B1 via resistors 42 and 42, respectively, and the emitters are connected to the negative power supply -B2.

Therefore, the collectors of the transistors 41a to 41y are supplied only during the pulse period of each driving pulse I to 41y.
Linear cathode drive pulses I' to Y' are output which have a low potential of B2 and a high potential of approximately 20 volts during other periods. Therefore, each line cathode 2
In addition to one end of 2yo, the other end is a diode 43i~4
Ground through 3yo. By doing this, each line cathode 2-2 is
A current is passed through it to heat it to a temperature at which it can emit electrons. However, during this high potential period, the potential at the line cathodes 2I to 2Y is higher than the potential at the positions of the line cathodes 2I to 2Y determined by the bias voltage applied to the back electrode 1 and the vertical focusing electrode 3. Since the high potential applied to is higher, no electrons are emitted. When the driving pulses I' to 2Y applied to each line cathode 2I to 2Y become a low-potential pulse period, each of the diodes 43I to 43Y is cut off, and the potential of line cathodes 2I to 2Y is turned off. becomes lower than the surrounding potential, so an electron beam is emitted. During this low potential pulse period, the line cathodes 2-2
Although heating current does not flow in y, electrons are sufficiently emitted by maintaining the heating state up to that point.

In this way, electrons are sequentially emitted from the line cathodes 2i to 2yo during the effective vertical scanning period from the upper line cathode 2a to the lower line cathode 2yo for 16H periods.
The screen is illuminated.

In the above embodiment, the counter decoder 38 was used as a means for creating the vertical drive pulses I to Y, but in addition to this, a monostable multivibrator that generates pulses for each 16H period was used.
They may be connected in series, and the first stage thereof may be triggered by the pulse VBL of the output of the flip-flop 40 at the beginning of the effective scanning period.

Also, for the vertical blanking pulse VBL, in addition to the one in the above embodiment, the vertical synchronizing signal may be used as is, or it may be integrated once and then shaped into a waveform.
It may be created by any means.

Furthermore, the terms "horizontal direction" and "vertical direction" in the above explanation mean that the direction in which line units are displayed when displaying an image is the horizontal direction, and the direction in which the lines are stacked is the vertical direction. It is used in this sense, and is not directly related to the vertical and horizontal directions on the actual screen.

As detailed above, according to the present invention, when a screen is vertically divided into a plurality of sections and a plurality of lines are displayed by deflecting the electron beams in the vertical direction for each section, a plurality of electron beams can be displayed. The source can be easily and accurately controlled with a simple circuit configuration.
It is capable of displaying good images.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing the basic configuration of an example image display element used in the image display device of the present invention;
Figure 2 is an enlarged view of the screen, Figure 3 is a block diagram showing the basic configuration of the drive circuit of the device, and Figure 4 is a block diagram showing the basic configuration of the drive circuit of the device.
The figure is a circuit diagram of the vertical deflection section in the same circuit, and FIG. 5 is a waveform diagram showing its operation. 2,2i~2yo... line cathode, 3... vertical focusing electrode, 4... vertical deflection electrode, 9... screen, 1
3, 13'... Conductor, 25... Vertical drive pulse generation circuit, 26... Line cathode drive circuit, 27... Vertical deflection drive circuit, 38... Counter decoder,
39...monostable multivibrator, 40...flip-flop, 41i~41yo...transistor, 42i~42yo...resistor, 43i~43yo...
…diode.

Claims (1)

[Claims] 1 The screen on the screen is vertically divided into a plurality of sections, an electron beam generation source is provided in each section to generate an electron beam, and a plurality of vertical Deflection means is provided, and a vertical deflection signal is applied to each vertical deflection means to vertically deflect the electron beam to display a plurality of lines within each section, and to display a plurality of lines within the vertical scanning period. A drive circuit is provided to generate an electron beam by sequentially driving one of the electron beam generation sources for a certain period of time, and the start of operation of the drive circuit is controlled by a vertical blanking signal created in response to a vertical synchronization signal. An image display device characterized by: