JPS59123145A - Picture display device - Google Patents

Abstract

PURPOSE:To improve a picture quality while removing unevenness in brightness by surrounding the periphery of a linear electrode with an equipotential electrode in a device making luminous display by controlling electron beams emitted from plural linear cathodes by deflection electrodes and control electrodes. CONSTITUTION:A rear electrode 1 and an electron beam taking-out electrode 3A are provided before and behind a linear cathode 2. The electrode 3A is provided with electron beam taking-out windows 10A. The electric potential about equal to the potential of the linear cathodes 2a-2d when emitting electron beams is impressed both on the electrode 1 and the electrode 3A. The electron beams emitted from the linear cathode 2a-2d pass through the taking-out windows 10A of the electrode 3A while being accelerated by the electrode 3B having smaller windows 10B than the windows 10A and impressed with the voltage of higher potential than the electrode 3A. In this way, even when the peripheries of the linear electrodes 2a-2d have no large potential slope while there are positional displacement due to mechanical vibration of the linear cathodes 2a-2d or the positional unevenness of the linear cathodes 2a-2d generated on the assembly stage, no big influence is given to the emission quantity of the electron beams thus improving a picture quality by removing uneven brightness.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to controlling electron beams emitted from a plurality of linear cathode electron beam sources using electrodes such as deflection electrodes and control electrodes, and thereby controlling the electron beams on the fluorescent display surface of a screen. The present invention relates to a display device that emits light by emitting a focused electron beam to display an image.

Conventional Structure and Problems First, an example of the basic structure of the image display element used here will be described with reference to FIG.

This display element includes, in order from the back to the front, a back electrode 1, a line cathode 2 as an electron beam source, a vertical focusing electrode 3.
3', vertical deflection type +Ii4, electron beam flow control electrode 6,
A horizontal focusing electrode 6, a horizontal deflection electrode 7, an electron beam accelerated ionization 8, and a screen plate 9 are arranged.
These are housed within the evacuated interior of a flat glass bulb (not shown). A line cathode 2 serving as an electron beam source is stretched horizontally so as to generate an electron beam distributed linearly in the horizontal direction. In the figure, only four wires 2-2 are shown). In this actual winding example, it is assumed that 15 wires are provided. Let's say 2i~2yo. These wire cathodes 2 are constructed by coating the surface of a tungsten wire with a diameter of 10 to 2 μΦ with an oxide cathode material, 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. This back electrode 1 may be formed by a coating of electrically conductive material applied to the inner surface of the rear wall of the 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 2a to 2yo, and extracts the electron beam emitted from the line cathode 2 through the slit 10, and vertically focus in a direction.

The slit 1o may be provided with crosspieces at appropriate intervals in the middle, or alternatively, the slit 1o may be a row of through holes arranged horizontally at small intervals (or almost touching each other). Alternatively, it may be configured as a slit.

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 the insulating substrate 12. has been done. Then, a vertical deflection voltage is applied between the opposing conductors 13 and 13' to deflect the electron beam in the vertical direction. In this configuration example, the electron beam from one line cathode 2 is deflected to a position corresponding to 16 lines in the vertical direction by a pair of conductors 13 and 13'.

The 16 vertical deflection electrodes 4 constitute 16 pairs of conductors corresponding to each of the 15 line cathodes 2, and the electron beams are deflected to draw 240 horizontal lines on the screen 9. do.

Next, the control electrodes 6 are composed of conductive plates 16 each having a vertically long slit 14, and a plurality of control electrodes 6 are arranged horizontally in parallel at predetermined intervals. In this configuration example, 320 control type other conductive plates 151L 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 6 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.
, B, and each control electrode 6
The R, e, and H video signals are sequentially added to the . In addition, 320 sets of video signals for one line are simultaneously applied to the 320 control electrodes 6, 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 slits 16 (320 slits 16) facing the slits 14 of the control electrode 6. Each beam is focused horizontally into a narrow electron beam.

The horizontal deflection electrode 7 is connected to each of the slits 16.
- It consists of a plurality of conductive plates 18 arranged vertically in the middle position, and a horizontal deflection voltage is applied between each conductive plate 18 to deflect the electron beam of each pixel in the horizontal direction. Then, the R, G, and H phosphors are sequentially irradiated on the screen 9 to cause them to emit light. The deflection range is
In this embodiment, each electron beam has a width of one picture element.

The acceleration electrode 8 is composed of a plurality of conductive plates 19 provided horizontally at the same position as the vertical deflection electrode 4.
The speed of the electron beam is increased 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 a metal bank layer (not shown) is added thereto.

The phosphors 20 are provided with one pair of phosphors of three colors, RlG and B, for each slit 14 of the control electrode 60, that is, for each one horizontally divided electron beam. , applied in vertical stripes. In FIG. 1, the broken lines drawn on the screen 9 indicate divisions in the vertical force direction 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 that will be displayed. As shown in an enlarged view in FIG. 2, one section partitioned by these two has R, G, and B phosphors 20 for one picture element in the horizontal direction.
It has a width of 16 lines in the vertical direction.

The size of one section is, for example, 1 mm in the horizontal direction and 16 mm in the vertical direction.

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

In this embodiment, only one pair of R, (, H phosphors 20 for one picture element is provided for one control electrode 6, that is, for one electron beam, but for two picture elements) Of course, two or more pairs may be provided, and in that case, the R, G, and B video signals of the two or more picture elements are sequentially applied to the control electrode 5, and in synchronization with this, the horizontal A deflection is made.

Next, a television image is shown on this display element.
The basic +4'j configuration of the ζth drive circuit is shown in FIG. 3 and will be explained. 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, -v1 to the back electrode 1, v3. to the vertical focusing electrodes 3, 3'. 3'- A DC voltage of v6 is applied to the horizontal focusing electrode 6, a DC voltage of v8 is applied to the accelerating electrode 8, and a DC voltage of v9 is applied to the screen 9.

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 is configured to operate during an effective vertical scanning period (here, a period of 24 OH) excluding the vertical retrace period of vertical synchronization. 15 driving pulses each having a length of 16H period [
49 mouths...Y] is generated. This drive pulse [
11 ports, old...] are added to the line cathode drive circuit 26,
Here, it is reversed so that it is at a low potential only during each pulse period and at a high potential of about 20 volts during the other periods./This line is converted into a cathode drive pulse [477'...Yo'] and each wire cathode 2a, 20.・・・・・・Added to 2yo. Each line cathode 2a,...2yo is its driving pulse [
A current is passed between the high potentials of the driving pulses [A' to Y'], and the heated state is maintained so that electrons can be emitted even during the low potential period of the drive pulses [A' to Y']. As a result, electrons are emitted from the 15 line cathodes 2i to 2yo only during the 16H period when low potential drive pulses [a' to yo'] are applied to each of them. During the period when a high potential is applied, the potential applied to the line cathodes 2I to 2Y 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 higher potential of the wire is positive, no electrons are emitted from the wire cathodes 2i to 2yo. Thus, in the line cathode 2, electrons are emitted from the upper line cathode 2a toward the lower line cathode 2y in order for 16H periods during the effective vertical scanning period. The emitted electrons are pushed forward by the back electrode 1, pass through the opposing slits 10 of the vertical focusing electrode 3, and are focused in the vertical direction 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 l to y] and counts horizontal synchronization signals, and a conversion circuit that converts the count output from D/A. During the 16H period of each vertical drive pulse [I to Y], a pair of vertical deflection signals v and v/ that change in 16 steps by 1H are generated. The vertical deflection signals V and V' both have a center voltage of v4, and are configured to change in opposite directions such that V increases sequentially and V' decreases sequentially. These vertical deflection signals V and V' are applied to the electrode 13 of the vertical deflection electrode 4, respectively.
and 13', and as a result, the electron beams generated from each of the line cathodes 2i to 2yo are vertically deflected in 16 steps, and as mentioned earlier, one electron beam is reflected on the screen 9. The raster is deflected to draw 16 lines of raster one line at a time from the top.

As a result of the above, electron beams are emitted for 16H hours in order from the one above the 16 line cathodes 2A to 2Y, and each electron beam is sequentially emitted for one line from the top to the bottom within 15 sections in the vertical direction. By being deflected, the screen 9
At the top, the electron beam is vertically deflected by one line from the first line at the top to the 240th line at the bottom, and a total of 240 raster lines are drawn.

The electron beam thus vertically deflected is horizontally divided into 320 sections by the control electrode 5 and the horizontal focusing electrode 6 and extracted. Figure 1 shows one of these categories. The amount of passage of this electron beam is controlled for each section by a control electrode 5, and is focused horizontally by a horizontal focusing electrode 6 into a single thin electron beam.
The light is deflected horizontally in three steps by the horizontal deflection means described below, and is sequentially irradiated onto each of the R, G, and B phosphors 2° on the screen 9.

That is, the horizontal drive pulse generation circuit 28 is composed of three cascaded monostable multivibrators, etc.
Triggered by a horizontal synchronization signal, three horizontal drive pulses r, g, and b of equal pulse width are generated within one horizontal period. Here, as an example, each pulse width is about 17 μsec, and the effective horizontal scanning period is 50 μsec.
Three pulses r, g, and b are generated during μsec. These horizontal drive pulses r, g, and b are applied to the horizontal deflection drive circuit 29. This horizontal deflection drive circuit 29 is switched by the horizontal drive pulses r9g and b to generate a pair of horizontal deflection signals that change in three stages. :
h' is generated. Horizontal deflection signal.

Both h' have a center voltage of v7, and change in opposite directions such that h sequentially increases and h' sequentially decreases. These horizontal deflection signals h' are applied to electrodes 18 and 18' of horizontal deflection electrode 7, respectively. the result,
Each horizontally divided electron beam sequentially hits the R, G, and B phosphors of the screen 9 for 17 μs during each horizontal period.
It is horizontally deflected so that each beam is irradiated at the same time. However, in the display element of FIG. 1, one conductor 18 or 18'
are used to deflect the electron beams of two adjacent sections, and are designed to produce deflection effects in mutually opposite directions on those adjacent electron beams.
In the 320-section electron beam, the odd-numbered sections are R
-) If it is deflected in the order of G→B, then those in even-numbered categories are deflected in the reverse order of B→G→R, and so on.
Every other segment is deflected in the opposite direction.

Thus, in each line raster, the horizontal 3
The electron beams are R and G for each of the 20 sections.

Each phosphor 20 of B is sequentially irradiated.

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

Next, the modulation control portion of the electron beam will be explained.

First, the composite video signal applied to the television signal input terminal 23 is applied to the color demodulation circuit 30, where the R-Y and B-Y color difference signals are demodulated and the G-
The Y color difference signals are matrix-synthesized, and further, they are combined with the luminance signal Y to output R, G, and B primary color signals (hereinafter referred to as R, G, and B video signals). These R, G, and B video signals are applied to 320 sample and hold circuit sets 31a to 31n. Each sample-and-hold circuit set 312L to 31n has three sample-and-hold circuits for R, G, and B, respectively. The sample and hold outputs of these sample and hold circuit sets 31a to 31n are applied to holding memory sets 321L to 32n, respectively.

On the other hand, the sampling reference clock oscillator 33 is a PLL.
(phase-locked loop) circuit, etc., and generates a reference clock of approximately 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 period by a shift register, etc., so that the clock is clocked during the effective horizontal scanning period (approximately 50μ5ec) of the horizontal synchronization (63.5μsec). 320 sampling pulses 1-n are sequentially generated, and then one transfer pulse is generated. This sampling pulse a-n covers one line of the image to be displayed by 32 pixels in the horizontal direction.
It corresponds to each picture element when divided into 0 picture elements, and its position is controlled to always be constant with respect to the horizontal synchronizing signal H.

These 320 sampling pulses a-n correspond to the 320 sample-and-hold circuit sets 31a to 31, respectively.
As a result, the R and JB video signals of each picture element when one line is divided into 320 picture elements are individually sampled and held in each sample-and-hold circuit set 31a to 32n. Ru. After the sample and hold of 320 sets of R, G, and B video signals is completed, 320 sets of R, G, and B video signals are stored in the memory 32a.
~32n, the transfer pulses t are simultaneously transferred and held here for the next horizontal scanning period.

One line of JG and B video signals held in the memo IJs 32a to 32n are applied to 320 switching circuits 35a to 35n, respectively. switching circuit 35
a to 35n are R and G, respectively.

Each switching circuit 35a has individual input terminals of B and a common output terminal that sequentially switches and outputs them.
The output of ~35n is used as a control signal for modulating the electron beam and is sent to the 320 conductive plates 15a of the control electrode 5 of the display element.
~15n each separately. Each switching circuit 35a to 35n is a switching pulse generation circuit 36.
Switching is controlled simultaneously by switching pulses applied from the The switching pulse generation circuit 36 receives the pulse r+E+ from the horizontal drive pulse generation circuit 28 mentioned above.
The effective horizontal scanning period of about 5 μsec of each horizontal period is divided into three, and the switching circuits 351L to 36n are switched by about 17 μsea, and the R, G, H
The respective video signals are time-divided and outputted alternately and sequentially, and switching signals r, g, and b are generated to be supplied to the controlled ionization units 15a to 15n. However, in the switch 7 switching circuits 35a to 35n, the odd numbered switching circuits 35a, 35c...... are R→G→
The even-numbered switching circuits 3 are switched in the order of B.
5 b , '35 d ・=-35n is B −+
The switching is made in the order of G - + H.

What should be noted here is that the switching circuits 35a to 3
The supply switching of R, G, and H video signals at 5n and the horizontal deflection of the electron beam irradiation switching to the R, (r, and B phosphors) by the horizontal deflection drive circuit 29 are completely performed in both timing and order. This means that when the electron beam is irradiating the R phosphor, the irradiation amount of the electron beam is R.
(, B is controlled in the same way, and the light emission of the R, G, B combined light body of each picture element is controlled by the R, JB video signal of that picture element. , each picture element is displayed by emitting light according to the input video signal.Such control is performed simultaneously for 320 picture elements for one line, and one line of video is displayed.
18 more.

One video is displayed on the screen 9 by sequentially performing the 240-minute line starting from the upper line.

The above operations are performed on one input television signal.
This is repeated for each field, and as a result, a moving television image is displayed on the screen 9 in the same way as 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 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. This is used in an alpha sense, and is not directly related to the vertical and horizontal directions on the actual screen.

In this way, an image is displayed on this display device, but the overhead wire 2 tends to generate mechanical vibrations, and the vibrations of the wire shielding poles result in vibrations in the amount of emitted electron beams. , as well as the above-mentioned vibration and vertical deflection 19.

Drive pulses 13, 13' and line cathode drive pulses [A'
~Y'] appears as a brightness vibration of the image on the screen 9, which significantly deteriorates the image quality.

However, the electron beam emission ability of each of the multiple line cathodes is
Because each line cathode has variations in activation and assembly precision, it is often not uniform, and the above-mentioned non-uniformity in electron beam emission ability is due to the uneven brightness of each part of the image that each line cathode has. occurs, leading to deterioration of image quality.

Purpose of the Invention The present invention eliminates such conventional drawbacks, and provides an image display device that can display high-quality images with less unevenness in brightness due to mechanical vibration of the line cathode or non-uniformity in beam generation ability. The purpose is to provide.

Structure of the Invention In the present invention, by equalizing the potentials applied to the periphery of the line cathode or to the electrodes before and after the line cathode, or by minimizing the potential difference, beams caused by vibration of the line cathode or non-uniformity in the electron beam emission ability of each line cathode are eliminated. To prevent deterioration of image quality by reducing unevenness in emission amount.

DESCRIPTION OF EMBODIMENTS Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In this device, as shown in FIG. 4, a back electrode 1 and three electron beam extraction electrodes are provided before and after the line cathode 20. The electrode 3A is provided with an electron beam extraction window 10A. A voltage approximately equal to the potential of the line cathodes 2A to 2Y during electron beam emission is applied to both the back electrode 1 and the three electron beam extraction electrodes.

The electron beams emitted from the line cathodes 2i to 2yo are sent to the electrode 10.
The electron beam passes through the three extraction windows of A and is accelerated by the electrode 3B, which has a window 10B smaller than the electrode 3A and to which a voltage of a higher potential than the three electrodes is applied.

In the second configuration, since there is no large potential gradient around the line cathodes 2I to 2Y, the positional displacement of the line cathodes 2I to 2Y due to mechanical vibration or the assembly step 21. Even if there is non-uniformity in the positions of the linear cathodes 2i to 2yo, it will not have a large effect on the amount of electron beam emission, so mechanical vibrations of the linear cathodes 2i to 2yo or non-uniformity in the positions of the linear cathodes 2i to 2yo will Non-uniformity in the position of Y is less likely to affect the brightness of the screen on the screen, and it is possible to prevent uneven brightness and improve image quality. Furthermore, since the electrodes 3A and 3B do not absorb the electron beam, the utilization rate of the electron beam is improved. At this time, the electrode 3B may also serve as an electron beam flow control electrode.

Effects of the Invention As described above, according to the present invention, by surrounding the line cathode with an electrode having approximately the same potential as the line cathode at the time of beam emission, the mechanical vibration of the line cathode is suppressed. Even if the beam generation capacity of each line cathode is uneven, the amount of electron beam emitted can always be kept constant, and image quality can be improved by eliminating uneven brightness between each screen section corresponding to each line cathode. It is something.

[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, FIG. 2 is an enlarged view of the screen, and FIG. 3 is the basic configuration of the drive circuit of the device. The block diagram shown in FIG. 4 is an exploded perspective view of the main parts of an image display element used in an image display device according to an embodiment of the present invention. 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 accelerating electrode, 9...Screen, 20...Fluorescent material, 3A...Electron beam extraction electrode, 3B...Acceleration electrode. Name of agent: Patent attorney Toshio Nakao and one other person JP-A-59-123145 (8) Figure 4

Claims (1)

[Claims] an electron beam generation source consisting of a plurality of line cathodes; 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; an electrostatic deflection electrode that deflects the electron beam until it reaches the screen;
An image display characterized by comprising a control electrode that controls the intensity of emitted light by controlling the amount of the electron beam irradiated onto the screen, and the line cathode is surrounded by electrodes having an equal potential. Device.