JPS641994B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention focuses the electron beam on the fluorescent display surface of a screen by controlling the electron beam emitted from an electron beam source such as a linear cathode using an electrode such as a deflection electrode or a control electrode. It relates to a display device that emits light and displays an image by irradiating it with
The aim is to provide something that can prevent destruction during startup.

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 reproducibility of color display, and have not yet 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 a plurality of lines, and then divides it horizontally into a plurality of sections to display R, G, A television image is displayed as a whole by causing the B, etc. phosphors to emit light sequentially, and by controlling the amount of electron beam irradiation to the R, G, B, etc. phosphors using a color video signal. something was invented.

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 (hereinafter, four cathodes 2A to 2D). (only 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. and,
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. deter, and
It functions to push out the generated electron beam only in the forward direction. 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 5 are arranged horizontally in parallel 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 extracts the electron beam by dividing it 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 pixels 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 18 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.
Pairs of phosphors of 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 Figure 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.
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 for one picture element is provided 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 sequentially from the top to the bottom within 15 sections in the vertical direction, so that one line is formed on the screen 9 from the 1st line at the top to the 240th line at the bottom. The electron beam is vertically deflected minute by minute, creating a raster of 240 lines in total.

The electron beam thus vertically deflected is horizontally deflected by 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 conductor 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 object in the th category is deflected in the order of R→G→B, then the object in the corner number th category is deflected in the order of B→G→R.
It is deflected in the opposite direction every other section, and so on.

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

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 RY and BY color difference signals 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 held by memory sets 32a to 32n, respectively.
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 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 clock is used during the effective horizontal scanning period (approximately 50 μsec) of the horizontal period (63.5 μsec). 320 sampling pulses a to n are generated in sequence, followed by one transfer pulse. These sampling pulses a to n correspond to each picture element when one line of the video to be displayed is divided into 320 picture elements in the horizontal direction, and their positions are always constant with respect to the horizontal synchronizing 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.
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 are 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 the switching of the supply of R, G, and B video signals in the switching circuits 35a to 35n, and the horizontal switching of the irradiation of the electron beam to the R, G, and B phosphors by the horizontal deflection drive circuit 29. The deflection is synchronously controlled so that both the timing and the order of the deflections are exactly the same. As a result, when the electron beam is irradiating the R phosphor, the irradiation amount of the electron beam is R
The G and B phosphors are controlled in the same way by the video signal, and the light emission of the R, G, and B phosphors of each picture element is controlled by the R, G, and B video signals of that picture element. Each picture element is displayed by emitting light according to the input video signal. This control is performed simultaneously on 320 picture elements for one line to display one line of video, and an additional 240 picture elements are displayed.
This is done sequentially for the minute lines starting from the upper line, and one image is displayed on the screen 9.

The above-mentioned operations are repeated for each feed of the input television signal, and as a result, a moving television image is displayed on the screen 9 in the same manner as in a normal television receiver.

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.

The present invention provides an image display device including:
In particular, it relates to means for applying voltages to adjacent deflection and focusing electrodes.

An embodiment of the present invention will be described below with reference to FIGS. 4 to 6. In this embodiment, a horizontal focusing electrode 6 and a horizontal deflection electrode 7 shown in FIG. 1, a horizontal focusing electrode 6' (not shown) installed between the horizontal deflection electrode 7 and an accelerating electrode 8, Electrode 7
An example will be explained in which a voltage is applied to both.
FIG. 4 shows only these three electrodes.

For example, consider a case where, in such an electrode configuration, a voltage of 50 V is applied to the horizontal focusing electrode 6, a voltage of 300 V is applied to the horizontal deflection electrode 7, and a voltage of 400 V is applied to the horizontal focusing electrode 6'. Insulating spacers 37 and 38 are provided between the electrodes 6, 7 and 6', respectively. If the dielectric strength of the insulating spacers 37, 38 is, for example, 270V, each of the electrodes 6, 7,
6', first apply 400V to the horizontal focusing electrode 6', then apply 50V to the horizontal focusing electrode 6,
Finally, when applying different electrode voltages one after another, such as applying 300V to the horizontal deflection electrode 7, the insulation spacer 38 between the horizontal focusing electrode 6' and the horizontal deflection electrode 7 may be temporarily However, when a voltage exceeding the withstand voltage is applied, a problem arises in which breakdown voltage occurs.

Therefore, in this example, a certain voltage is simultaneously applied to the three electrodes 6, 7, and 6', and the voltages are then set independently to prevent dielectric breakdown from occurring.

5 and 6 show the desired voltages for each electrode 6, 7, 6', the power supply configuration, and the voltage application method. Again, the voltage V ₆ applied to the horizontal focusing electrode 6
is 50V, the voltage V _{7 applied to the horizontal deflection electrode 7} is 300V,
The explanation will be made assuming that the voltage V _{6 ' applied to the horizontal focusing electrode 6} ' is 400V. In FIG. 6, E ₁ , E ₂ , and E ₃ indicate power supplies for providing these voltages, respectively.

First, the power in the first step _E1 is turned on, and a voltage of the same value, _V7 (=300V), is simultaneously applied to each electrode 6, 7, 6'. Next, in the second step, turn on the power source _E2 and apply the voltage to the horizontal focusing electrode 6'.
Raise to V ₆ ′ (=400V). Then, in the third step _E3 , the power is turned on and the voltage applied to the horizontal focusing electrode 6 is lowered to _V6 (=50V). That is,
First, the horizontal focusing electrodes 6, 6' and the horizontal deflection electrode 7 are
Apply the same voltage of 300V at the same time, then
The voltage applied to the horizontal focusing electrodes 6, 6' is raised to the required voltage (50V, 400V) and then lowered.

In this way, by applying the necessary voltage to each electrode 6, 7, 6', the insulating spacer 3
When the breakdown voltage of electrodes 7 and 38 is 270V, the potential difference between each electrode 6 and 7 and between each electrode 7 and 6' will not exceed the above breakdown voltage, and no dielectric breakdown will occur.

In the above embodiment, 300V is first applied to each electrode 6, 7, 6' at the same time, and then the horizontal focusing electrode 6' is raised to 400V, and the horizontal focusing electrode 6 is lowered to 50V. may be applied at the same time and then lowered to 300V and 50V, respectively, and the same effect as in the above embodiment can be obtained. Also, in the first step,
The power of E ₁ may be turned on and off by switching, but in the second and third steps, the power of E ₂ and E ₃
It goes without saying that it is safer not to switch the power supply on and off.

As described above, according to the present invention, when the potential difference between the voltages applied to adjacent electrodes is close to the withstand voltage of the insulating spacer arranged between the electrodes, first a certain voltage is applied to each of the electrodes. Apply at the same time,
After that, by independently applying a voltage higher or lower than the applied voltage to the electrodes to which the voltage should be applied, a potential difference exceeding the withstand voltage of the insulating spacer does not occur, and the insulating spacer It can be reliably protected from destruction.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of an example display element used in the image display device of the present invention, FIG. 2 is an enlarged front view of the screen, FIG. 3 is a block diagram showing the basic configuration of the drive circuit, and FIG. 5 is a chart diagram illustrating the operation of an image display device according to an embodiment of the present invention, and FIG. 6 is a partial circuit diagram thereof. 2... line cathode as an electron beam source, 3,3'
...Vertical focusing electrode, 4... Vertical deflection electrode, 5...
Beam flow control electrode, 6...Horizontal focusing electrode, 7...
horizontal deflection electrode, 8...beam accelerating electrode, 9...screen, 20...phosphor, 23...input terminal,
24... Synchronization separation circuit, 25... Vertical drive pulse generation circuit, 26... Line cathode drive circuit, 27... Vertical deflection drive circuit, 28... Horizontal drive pulse generation circuit, 29... Horizontal deflection drive circuit, 30 ...Color demodulation circuit, 31a-31n...Sample hold circuit group, 32a-32n...Memory group, 34...Sampling pulse generation circuit, 35a-35n...Switching circuit, 36...Switching pulse generation circuit, 37 , 38...Insulating spacer.

Claims (1)

[Claims] 1. An electron beam generation source, a screen having a phosphor that emits light when irradiated with the electron beam, a focusing electrode that focuses the electron beam generated by the electron beam generation source, and a screen that focuses the electron beam on the screen. an electrostatic deflection electrode that deflects between the electron beam and the screen, a control electrode that controls the emission intensity by controlling the amount of irradiation of the electron beam and the screen, and an insulating electrode that is arranged between each of the electrodes. An image display element equipped with a spacer is provided, and when a voltage approximately equal to the dielectric strength voltage of the insulating spacer is applied between adjacent electrodes via the insulating spacer, a voltage of a certain value is simultaneously applied to these adjacent electrodes. is applied, and then a voltage higher or lower than the constant voltage is applied to the electrode to be applied and independently adjusted to the desired voltage, thereby preventing dielectric breakdown of the insulating spacer. image display device.