JPS6352834B2 - - Google Patents

Description

[Detailed Description of the Invention] Traditionally, 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 and are thin compared to the screen size. It would have been impossible to create a television receiver. 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 reproducibility of color display, and have not been put into practical use.

Therefore, the aim was to create a device that could display color television images on a flat display device using electron beams, and the screen was divided vertically into multiple sections. Each section generates an electron beam, deflects each electron beam in the vertical direction to display multiple lines, and further divides it into multiple sections horizontally to display R, G, B, etc. phosphors are made to emit light in sequence, and the amount of electron beam irradiation to the R, G, B, etc. phosphors is controlled by a color video signal, and the television image as a whole is displayed. Something to display was devised.

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.
Back electrode 1, line cathode 2 as an electron beam source, vertical focusing electrodes 3, 3', vertical deflection electrode 4, electron beam flow control electrode 5, horizontal focusing electrode 6, horizontal deflection electrode 7, electron beam accelerating electrode 8 and screen. Board 9
These are housed in the evacuated interior of a flat glass bulb (not shown). Line cathode 2 as electron beam source
is stretched in the horizontal direction so as to generate an electron beam distributed linearly in the horizontal direction, and a plurality of such linear cathodes 2 are arranged vertically at appropriate intervals (here, 2 A to 2 D). (Only books shown) provided. In this embodiment, it is assumed that 15 pieces are provided. Let's say 2i~2yo. These wire cathodes 2 are constructed by applying an oxide cathode material to the surface of a tungsten wire having a diameter of 10 to 20 μΦ, for example. 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. The back electrode 1 creates a potential gradient with a vertical focusing electrode 3, which will be described later, and prevents the generation of electron beams from other line cathodes 2 other than the line cathode 2 which is controlled to emit electron beams for a certain period of time. It has the function of suppressing the electron beam and pushing the generated electron beam forward only. 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 configuration example, 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 configuration example, 320 control electrode conductive plates 15a to 15n 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. Also,
In order to display images in color, each picture element is R,
Display is performed using phosphors of three colors, G and 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.
Video for each line is displayed at once.

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 dashed lines indicate the divisions in the vertical direction that are displayed corresponding 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 cause the phosphor to emit light and generate a raster 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 retrace pulse and counts horizontal pulses, and the vertical retrace pulse generation circuit 25 is configured with a counter that is reset by a vertical retrace pulse and counts horizontal pulses, and the vertical retrace pulse generation circuit 25 is configured to operate during an effective vertical scanning period (here, 240H) excluding the vertical retrace period of the vertical period. 15 drive pulses each having a length of 16H are generated sequentially during each period of 16H. These drive pulses I, B...Y are applied to the line cathode drive circuit 26, where they are inverted so that they are at a low potential only during each pulse period and approximately
The line cathode drive pulses made at a high potential of 20 volts are converted into line cathode drive pulses I', B'...Y', and each line cathode 2I, 2
(b)...Added to 2 (yo). Each line cathode 2,...2
A current is applied to Y during the high potential of the drive pulses I' to Y', and the heated state is maintained so that electrons can be emitted even during the low potential period of the drive pulses I' to Y'. As a result, electrons are emitted from the 15 line cathodes 2i to 2yo only during the 16H period in which low-potential drive pulses I' to Y' are applied to each of them. 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, no electrons are emitted from the line cathodes 2I to 2Y. Thus, in the line cathode 2, electrons are sequentially emitted from the upper line cathode 2a toward the lower line cathode 2y every 16H period during the effective vertical scanning period. The emitted electrons are transferred to the back electrode 1
The electron beam is pushed forward by the electron beam, passes through the opposing slit 10 of the vertical focusing electrode 3, and is focused in the vertical direction to form a flat electron beam.

Next, the vertical deflection drive circuit 27 is composed of a counter that is reset by each of the vertical drive pulses y to y and counts the horizontal synchronizing signal, and a conversion circuit that converts the count output from D/A. , generates a pair of vertical deflection signals v and v' that change in 16 steps by 1H during the 16H period of each vertical drive pulse. 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 for 16H periods starting from the one above the 15 line cathodes 2I to 2Y.
Each electron beam is deflected one line at a time from the top to the bottom within the 15 sections in the vertical direction, so that the electron beams are deflected one line at a time from the 1st line at the top to the 240th line at the bottom on the screen 9. The electron beam is vertically deflected line by line, creating 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 sequentially.

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. Therefore, the electron beam of 320 sections is If the thing in the th category is deflected in the order of R→G→B, the thing in the even numbered category 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 3.
Added to 1n. Each sample hold circuit group 3
1a to 31n each have three sample and hold circuits for R, G, and B. The sample and hold outputs of these sample and hold circuit sets 31a to 31n are stored in memory sets 32a to 32 for holding, respectively.
Added to 2n.

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 about 6.4 MHz in this embodiment. The reference clock is controlled to always have 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, etc. sampling pulses a to n are generated sequentially, and then 1
transfer pulses are 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.

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 31n.
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.
32n all at once by a transfer pulse t,
Here, it is held for the next one horizontal scanning period.

One line of R, G, and B video signals held in the memories 32a to 32n are applied to 320 switching circuits 35a to 35n, respectively. The switching circuits 35a to 35n each have R, G,
B individual input terminals and a common output terminal that sequentially switches and outputs them, and the output of each switching circuit 35a to 35n is sent to the control electrode 5 of the display element as a control signal for modulating the electron beam.
are individually applied to each of the 320 conductive plates 15a to 15n. Each switching circuit 35a to 35
n are simultaneously switched and controlled by a switching pulse applied from a switching pulse generating circuit 36. The switching pulse generation circuit 36 receives pulses r,
g and b, and the switching circuits 35a to 35n are switched by dividing the effective horizontal scanning period of about 50 μsec in each horizontal period into three and switching the switching circuits 35a to 35n for about 17 μsec each.
The R, G, and B video signals are time-divisionally output alternately and sequentially, and switching signals r, g, and b are generated to be supplied to the control electrodes 15a to 15n. However, among the switching circuits 35a to 35n, the odd numbered switching circuits 35a, 35c...
→B, and the even-numbered switching circuits 35b, 35d...35n are switched in the order of B→G→
The switching is made in the order of 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 electron beam irradiation to the R, G, and B phosphors by the horizontal deflection drive circuit 29 are performed in both timing and order. This means that they are synchronously controlled so that they match perfectly. 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 displayed on this display device.

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

Next, FIG. 4 shows the basic configuration of the vertical deflection drive circuit 27. The ring counter 37 is reset at the leading edge of each of the vertical drive pulses E through Y from the vertical drive pulse generation circuit 25, and then counts the horizontal synchronizing signal H and sequentially outputs signals from the 16 output terminals.
Switching pulses α to π are generated every 1H. On the other hand, the variable resistor 38 is provided with 16 output terminals, from which 16 levels of output voltage for vertical deflection are taken out, and the analog switches 39α to 39
It is taken out via 9π. Each analog switch 39α to 39π is switched to conduct for 1H period in sequence by the respective switching pulses α to π, and the output is divided into 16 stages between the lowest terminal and the highest terminal, and the level increases sequentially. is obtained. The output voltage is taken out via a transistor 40 connected as an emitter follower, the amplitude is adjusted by a variable resistor 41, and further amplified by a class B amplifier circuit 45 composed of transistors 42, 43, and 44. As a result, a vertical deflection signal v is generated from the output terminal 46. On the other hand, the vertical deflection signal v' is also created by a completely similar circuit, but the only difference from the above case is that the analog switches 39α' to 39π' are switched in the reverse order by the switching pulses α to π. This creates a step-like output v' whose level gradually decreases, and output terminal 46'
is output from.

The vertical deflection signals v and v′ thus created are the first
As shown in the figure, the conductive plates 13 and 1 of the vertical deflection electrode 4
3', whereby the electron beam is deflected in 16 steps within each section in the vertical direction, and a raster of 16 lines is drawn with one electron beam.

However, when the deflection occurs, the distance from the center of deflection to the screen 9 is different, so the interval between the upper and lower lines of the raster in one section becomes wider, and the high pressure applied to the surface of the screen 9 causes the upper And the spacing between the lines at the bottom becomes narrower. Therefore, in order to equalize the spacing between each line, the output terminal voltages of the variable resistors 38 and 38' are adjusted one by one, and the deflection voltage is corrected to make the raster line spacing uniform. This method has the disadvantage that there are many points to be adjusted, and it takes time to make adjustments, making it unsuitable for production.

The present invention is intended to solve these drawbacks, and one embodiment thereof is shown in FIG.

The method of creating a stepped deflection waveform is the same as in the conventional method, but in this device, a fixed resistor 50 is used instead of the conventional variable resistor 38. The step-like deflection waveform obtained thereby has voltage differences at equal intervals.

Newly added circuits 51 to 66 are gain adjustment circuits made up of differential amplifiers made up of transistors 58 to 63. transistor 6
1,62 base voltage is transistor 60,63
When the voltage rises above the base voltage of , the output amplitude increases. The input is provided to the base of transistor 58. The bases of transistors 60 and 63 are resistors 5
4.55 and is fixed at an appropriate voltage (approximately Vcc/2). On the other hand, the analog switch 51 is turned on in the transistors 61 and 62 by switching pulses .alpha. to .pi. every 1H using the voltage obtained by the regulator 52 and the resistors 53 to 55, and the voltage shown in FIG. 6b is obtained. A in b is when the volume 52 is set to Vcc/2, and the output 66 at this time becomes a deflection voltage at equal intervals as in a. When the volume 52 is set to the Vcc side, V _A becomes as shown in b (b), and the output 66 becomes the deflection waveform shown in a (b) with upward and downward expansion. On the other hand, when the volume 52 is set to the ground side, V _A becomes as shown in c in b, and the output 66 becomes a deflection waveform shown in c in a for the upper and lower jams. In this way, the volume 52
Any waveform between a and b can be created with one waveform, and the spacing between lines within one section, which was a problem in the past, can be easily adjusted to be uniform. This output 66 is supplied to the deflection output circuit via a conventional transistor 40 to the conductive plate 13 of the vertical deflection electrode 4,
13'.

As described above, according to the present invention, it is possible to display the lines in each section at equal intervals, and it is possible to display a television image satisfactorily.

[Brief explanation of the drawing]

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.
5 is a circuit diagram of a basic circuit example of the vertical deflection drive circuit, FIG. 5 is a specific circuit diagram of a main part of an image display device according to an embodiment of the present invention, and FIG. 6 is a waveform diagram illustrating its operation. 2... line cathode as an electron beam source, 3,3'
...Vertical focusing electrode, 4... Vertical deflection electrode, 5...
Electron beam flow control electrode, 6...Horizontal focusing electrode, 7
...Horizontal deflection electrode, 8...Electron beam acceleration electrode,
9... Screen, 20... Fluorescent material, 23... Input terminal, 24... Synchronization separation circuit, 25... Vertical drive pulse generation circuit, 26... Line cathode drive circuit, 2
7...Vertical deflection drive circuit, 28...Horizontal drive pulse generation circuit, 29...Horizontal deflection drive circuit, 30...
...Color demodulation circuit, 31a to 31n...Sample and hold circuit group, 32a to 32n...Memory group, 34
...Sampling pulse generation circuit, 35a to 35
n... Switching circuit, 36... Switching pulse generation circuit, 50... Resistor, 51... Analog switch, 52... Volume, 53, 54, 5
5, 56...Resistance, 58, 59, 60, 61, 6
2, 63...Transistor, 64, 65...Resistor.

Claims (1)

[Claims] 1 The screen on the screen is vertically divided into multiple sections, an electron beam is generated for each section, and each electron beam is deflected vertically for each section to display multiple lines. As a means for supplying a vertical deflection signal for vertically deflecting the electron beam in each of the above sections of the image display, one
means for creating a stepped waveform signal with a fixed voltage for each horizontal scanning line; a variable gain circuit that receives the stepped waveform signal as an input; gain switching means for switching the gain of the variable gain circuit in synchronization with the switching pulse so that the plurality of lines are equally spaced by sequentially increasing or decreasing the voltage for each scanning line; An image display device comprising: an amplification circuit that amplifies an output to produce a vertical deflection signal.