JPS5881388A - image display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention vertically divides a screen into a plurality of sections and generates an electron beam for each section.
This relates to a device that displays a television image as a whole by deflecting each electron beam vertically for each segment to display multiple lines, and when the electron beam is deflected vertically, the deflection angle The object of the present invention is to provide a device that can make corrections to make the phosphor spot size on the screen constant regardless of the size of the phosphor spot on the screen.

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 to do so. Although 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 displays. , it has not yet been put into practical use.

Therefore, in order to achieve a device that can display color television images on a flat display device using electron beams, the screen is divided vertically into multiple sections, and each section is divided into two sections. generates an electron beam,
The electron beams are deflected vertically for each section to display multiple lines, and are further divided horizontally into multiple sections and fluorescent lights such as R-G-B are applied to each section. A system was devised in which the body was made to emit light in sequence, and the amount of electron beam irradiation to the R-G, B, etc. phosphors was controlled by color video signals, and a television image was displayed 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 has a back electrode 1. Line cathode as electron beam source2. Vertical focusing electrode 3.
3', vertical deflection electrode 4. Electron beam flow control electrode5. Horizontal focusing electrode 6. A horizontal deflection electrode 7°, an electron beam accelerating electrode 8 and a screen plate 9 are arranged.1. ,
-These are housed inside 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. Deba2i~2
(Only four of the two are shown). In this embodiment, it is assumed that 15 pieces are provided. This is 2-2
Let's do it. These line cathodes 2 have a diameter of, for example, 10 to 2oμφ.
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.

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 film of a conductive material attached to the inner surface of the rear wall of the glass bulb. An electron beam emitting cathode may also be used.

The vertical focusing electrode 3 is a conductive plate 11 having a horizontally long slit 1o facing each of the line cathodes 2a to 2yo, and takes out the electron beam emitted from the line cathode 2 through the slit 1o, and vertically focus in a direction.

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

The vertical focusing electrode 3' is also similar.

A plurality of vertical deflection electrodes 4 are arranged horizontally at intermediate positions of the slits 1o, and conductors 13, 13 are provided on one side and the bottom side of the insulating substrate 12, respectively.
' is provided. 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, a pair of conductors 13 and 13' direct the electron beam from one line cathode 2 to a position corresponding to 16 lines in the vertical direction.
deflect.

The 16 vertical deflection electrodes 4 constitute 15 pairs of conductors corresponding to each of the 16 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 15 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 conductive plates 16a to 15n for control electrodes are provided (only 1° is shown in the figure). Each of the control electrodes 5 extracts the electron beam horizontally by dividing it into one picture element at a time, and controls the amount of electron beam passing therethrough in accordance with the 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.
, H, and each control electrode 5
The R, G, and B 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 5, 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, and collects electrons for each picture element divided in the horizontal direction. Each beam is focused horizontally into a narrow electron beam.

The horizontal deflection electrode 7 is made up 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 pixel. The electron beams are respectively deflected in the horizontal direction, and the R, G, and H 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 is designed to cause the electron beam to collide with the screen 9 with sufficient energy. To accelerate.

The screen 9 is constructed by applying a phosphor 2o that emits light when irradiated with an electron beam to the back surface of a glass plate 21, and adding a metal back layer (not shown).

The phosphors 2o are provided with one pair of phosphors of three colors, R2G and B, for each slit 14 of the control electrode 6, that is, for each horizontally divided electron beam. It is applied in vertical stripes.

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 2 o's of R, G, and B phosphors for one pixel 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.
, 16 in the vertical direction.

Note that in FIG. 1, the length in the horizontal direction is drawn much larger than the length in the vertical direction for the sake of 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 6, that is, one electron beam, but for two or more picture elements. Of course, two or more pairs of pixels may be provided; in that case, R, G, and B video signals for two or more picture elements are sequentially applied to the control electrode 6, and the horizontal deflection is synchronously applied to the control electrode 6. It will be done.

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. The focusing electrode 6 has v6. 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 cover an effective vertical scanning period (in this case, 24 OH) excluding the vertical retrace period of the vertical period. 15 drive pulses (42 pulses, . . . ) each having a length of 16H periods are sequentially generated during each period (referred to as a period). This drive pulse [
] is applied to the line cathode drive circuit 26, where it is inverted so that the line is brought to a low potential only during each pulse period and to a high potential of about 20 volts for the rest of the time. It is converted into cathode driving pulses [479'-...Y'], and each line cathode 2, 20. ...Added to 2yo.

Each line cathode 2a.

-...2 yo is a current flowing during the high potential of the driving pulse [A' to YO'], and the current is flowing between the driving pulses [A' to YO']
The heated state is maintained so that electrons can be emitted even during the low potential period. As a result, electrons are emitted from the 15 line cathodes 2i to 2yo only during the 1eH period when low potential drive pulses [a' to yo'] are applied to each of them. During the period in which 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 line cathode 2 is positive,
No electrons are emitted from I~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 1o of the vertical focusing electrode 3, and are focused in the vertical direction to form a flat electron beam.

Next, the vertical deflection and drive circuit 27 generates a vertical drive pulse [A to
It consists of a counter that is reset by each of the vertical drive pulses C to count horizontal synchronizing signals, and a conversion circuit that converts the count output to D/A, etc. During the 16H period of each vertical drive pulse C, A pair of vertical deflection signals v9. which change in 16 steps by 1H. Generate and do v'. 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. The electron beams applied to these electrodes 13 and 13', and as a result, the electron beams generated from the respective line cathodes 2I to 2Y are vertically deflected in 16 steps. One electron beam is deflected to draw a 16-line raster one line at a time, starting from the top.

As a result of the above, electron beams are emitted for a period of 1eH in order from the one above the 16 line cathodes 2I to 2Y, and each electron beam is sequentially emitted for one line from the top to the bottom within the 15 sections in the vertical direction. By being deflected, the screen e
At the top, the electron beam is vertically deflected one line at a time from the first line at the top to the 240th line at the bottom, and a total of 240 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 passing of this electron beam is controlled by the control electrode 6 for each section, and it is focused horizontally by the horizontal focusing electrode 6 into a single thin electron beam, which is then horizontally focused by the horizontal deflection means described below. screen deflected into stages 9
-E's R, Ci, and E phosphors 20 are sequentially irradiated.

That is, the horizontal drive pulse generation circuit 28 is composed of three cascaded monostable multivibrators, etc.
Triggered by the water synchronization signal, three horizontal drive pulses r, g, with equal pulse widths are generated within one horizontal period.
generate b. Here, as an example, three pulses r + q + b are generated during an effective horizontal scanning period of 50 μsec, with each pulse width being about 17 μsec. Those horizontal drive pulses r,
g and b are applied to the horizontal deflection drive circuit 29. This horizontal deflection drive circuit 29 uses a horizontal drive pulse r + CJ +
A pair of horizontal deflection signals h and h' are generated by being switched by b and changing in three stages. Horizontal deflection signal.

Both h' have a center voltage of v7, and change in opposite directions 4 such that h increases and increases sequentially and h' decreases sequentially. These horizontal deflection signals h 1 and h' are applied to electrodes 18 and 18' of the horizontal deflection electrode 7, respectively. As a result, each horizontally segmented electron beam passes through the screens 90R,G during each horizontal period.

The light is horizontally deflected so that the phosphor B is sequentially irradiated for 17 μsec. However, in the display element of FIG. 1, in the horizontal deflection electrode 7, one conductor 18 or 18' is used for deflecting the electron beams of two adjacent sections. Since the electron beams are deflected in opposite directions, the electron beams in 320 sections are divided into odd-numbered sections.
If the beams are deflected in the order of H, the even-numbered sections are deflected in the order of BGH, and so on, and so on, and so on, and so on, so that every other section 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 2o of B is sequentially irradiated.

Therefore, for each horizontal section of each line, the R and G electron beams are
, H video signals 15, it is possible to display a color television image 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 3o, where the R-Y
and B-Y 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, and B primary color signals (hereinafter referred to as R, G, A B video signal) is output. These R, G, and B video signals are processed by 320 sample and hold circuit sets 31a to 3.
Added to 1n. Valley sample hold circuit group 31a~
3In each has three sample and hold circuits for R, G, and B. The sample and hold outputs of these sample and hold circuit sets 31a to 31fl are applied to holding memory sets 32a to 32H, respectively.

On the other hand, the sampling reference clock oscillator 33 is a PLL.
(Phase Locked Loop) circuit, etc., and generates a 6.4 MHz reference clock 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 the frequency register, etc., so that during the effective horizontal scanning period (approximately 50 μsec) of the horizontal period (63.5 μ5 ec), 320
sampling pulses a % n are generated in sequence, followed by one transfer pulse. These sampling pulses a - 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 320 sample and hold circuit sets 31a to 31H, respectively.
is added to each sample-and-hold circuit set 3.
In 1a to 31H, when one line is divided into 320 picture elements, R, G, and B video signals of each picture element are individually sampled and held. The 320 sets of R, G, and B video signals sampled and held are transferred all at once to 320 sets of memories 32a to 32n by a transfer pulse t after the completion of sample and hold for one line, where they are used for the next horizontal scanning period. held for a while.

One line of R, G, and B video signals held in the memo IJs 32a to 32n are applied to 320 switching circuits 35a to 35n, respectively. switching circuit 3
58 to 35n are R and G, respectively.

゛ It has individual input terminals of B and a common output terminal that sequentially switches and outputs them, and the valley switching circuit 3
The outputs of 5a to 35n are used as control signals for modulating the electron beam to control electrodes 60 and 320 conductive plates 1 of display elements.
5a to 15n individually. The switching circuits 35a to 35n are simultaneously controlled by switching pulses applied from the switching pulse generating circuit 36. The switching pulse generation circuit 36 receives pulses r and q1 from the horizontal drive pulse generation circuit 28 described above.
8b, the effective horizontal scanning period of each horizontal period is divided into three by about 50μ8eC, and the switching circuits 35a to 35n are switched by about 1711SeC, and the R, G, B
A switching signal rrq+ is applied so that each video signal of
generate b. However, the switching circuits 35a to 35
In H, odd-numbered switching circuits 35a, 35
c... are switched in the order of R→G-, B, and the even-numbered switching circuits 36b, 35d--35n are switched in the reverse order of BGR.

What should be noted here is that the switching circuits 35a to 3
The supply switching of R, G, and B video signals at 5n and the horizontal deflection of the electron beam irradiation switching to the R, G, and B phosphors by the horizontal deflection drive circuit 29 are completely performed in both timing and order. They are 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 H are also controlled in the same way, 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 votive tablet, and each picture element is displayed by emitting light according to the input picture signal. Such control is 320 for one line.
The process is performed simultaneously for each picture element to display one line of video, and the process is performed sequentially for 240-minute lines starting from the upper line, so that one video is displayed on the screen 9.

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 projected on the screen 9 in the same way as in a normal television receiver.

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. It is used in this sense, and is not directly related to the vertical and horizontal directions on the actual screen.

A revision image is projected, but since the path that the electron beam passes through varies depending on the deflection angle of the vertical deflection, the beam spot diameter may differ on the screen 9, and the beam may be distorted in the horizontal or vertical direction. Sometimes. When viewed as a television image on the screen 9, this results in repeated distortion every 16 lines, which is perceived as a horizontal line.

Therefore, an object of the present invention is to provide a device that makes it possible to obtain a highly uniform image in the vertical direction as a television image on the screen 9 in such a case.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing the configuration of its main parts.

What is shown in FIG. 4 is a schematic view of one section of spots divided horizontally and vertically on the screen 9 when a direct current type voltage is applied to the vertical focusing electrode 3. As a result of being deflected by the vertically deflecting electrode 4, the spots formed by the greatly deflected upper and lower electron beams have shapes that are slightly elongated in the vertical direction.

This is because, as understood from FIG. 5, an electron beam with a large deflection angle passes through each electrode diagonally, and the focusing electrode effect becomes weaker than that of an electron beam centered on deflection.

Therefore, as shown in FIG. 6, every 1 eH is applied to the vertical focusing electrode 3.
That is, this distortion of the beam spot is corrected by superimposing a parabolic waveform correction voltage corresponding to one vertically divided section. As a result, a stronger focusing effect can be given to electron beams with a large deflection angle, that is, electron beams that have traveled a long distance from the cathode.
As a result, the beam spot on the screen 9 can be made to have the same shape as the spot at the center of deflection, and an image with high uniformity in the vertical direction can be reproduced on the screen e.

A circuit of an embodiment that performs the above four operations is shown in FIG. 7 and will be described. In the conventional system, the two beam focusing voltages V and v3' are DC voltages as shown in FIG. 3, but a parabolic waveform voltage as shown in FIG. 6 is superimposed thereon. In order to create this parabola correction voltage, it is obtained by D/A converting 6 bits of digital data.

First, the OR gate 37 calculates the logical sum of 15 - cathode drive pulses A, B, - Y to create a pulse for 240 horizontal periods, which is an effective signal period, that is, a display period, and inputs it to the AND gate 38. On the other hand, a horizontal synchronizing signal is applied to the other input of the AND gate 38. As a result, the output of the AND gate 38 is a train of 240 horizontal pulses during the display period, each pulse having a period of 1H and the repetition period of the entire pulse group being 1V. Next, this pulse train is inputted as a clock to the 4-bit counter 39. This counter 39 is connected to be cleared by the vertical synchronizing signal V. As a result, if the counter 39 is configured with an amplifier counter, the increment operation from "oooo" to "1111" is continuously performed by 1 during the -vertical period.
Repeat this 23 times 6 times. That is, every 16 water periods °'ooo"
~” Repeat 1111°゛.

This 4-bit count output is input to the decoder 40. This decoder 4o is used to control the address of a memory 41, which will be described next, and when a general-purpose memory is used, this decoder 4o is often built-in. memory 4
1 consists of 6 bits x 16. This has the characteristics of a preset memory, and normally there is no need to change it once it is set. That is, it is sufficient to have a preset function for variations in display elements. Furthermore, the meaning of 6-bit is related to the resolution of the output correction voltage, and experiments have shown that 6-bit, ie, 64-step resolution, poses no problem in practice. of course,
If higher resolution is required, the number of bits can be increased.

On the other hand, the address is deflected in 16 steps in the vertical direction, and is preset to obtain the optimum correction voltage corresponding to each. The memory 41 is sequentially addressed by the decoder 40, and 6-bit data is output to the D/A converter 42 for each address. Positive and negative reference voltages are applied to this D/A converter 42 to determine the DC level and variable width of the output. With this configuration, it is possible to obtain an optimal correction voltage that can correct the spot size so that it does not change even when deflected in the vertical direction.

Although the capacitor 43 connected between the output terminal and the ground is not necessary in the basic configuration, it is actually inserted to remove unnecessary switching noise. the result,
A parabolic waveform correction voltage as shown in FIG. 6 is obtained.

In this case, the potential changes somewhat during one horizontal period, but this does not pose any practical problem.

Further, as the polarity of the output waveform, a waveform with a polarity opposite to that shown in FIG. 6 may be required. This depends on the electrode configuration mentioned above and is not uniformly determined.

However, according to this configuration, even if the polarity or a more complicated modulation waveform for correction is required, the original data is composed of the digital signal 5 and stored in the memory 41.
Any waveform can be generated as long as the day and evening are changed, so corrections can be made without any problems.

Of course, the correction voltage for beam spot correction can be created by any other means.

As described above, according to the present invention, the screen on the screen is vertically divided into a plurality of sections, an electron beam is generated for each section, and each electron beam is deflected vertically for each section. When the electron beam is deflected in the vertical direction in each section, the distortion of the shape of the beam spot that occurs when the electron beam is deflected in the vertical direction in each section is reduced by focusing and deflecting. Correction can be made by applying a correction voltage that changes with the deflection, such as a parabolic shape, to the electrodes, and an image with good resolution can be displayed with a uniform beam spot shape over the entire area.

[Brief explanation of the drawing]

6. Figure 1 is an exploded perspective view showing the basic configuration of an example of an image display element used in the image display device of the present invention, Figure 2 is an enlarged view of the screen, and Figure 3 is the basic configuration of the drive circuit of the device. 4 is a front view showing the beam spot on the screen, FIG. 6 is a schematic diagram showing the vertical deflection state, and FIG. 6 is the operation of the image display device in one embodiment of the present invention. FIG. 7 is a block diagram of the main parts of the device. 2... line cathode as an electron beam source, 3,3'...
... Vertical focusing electrode, 4 ... Vertical deflection electrode, 6
...Electron beam flow control electrode, 6...Horizontal focusing electrode, 7
... Horizontal deflection electrode, 8 ... Electron beam acceleration electrode, 9 ... Screen, 2o. Fluorescent material, 23 ...
・Input terminal, 24...Synchronization separation circuit, 26...
- 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, 3
o Color demodulation circuit, 31a to 31n Sample and hold circuit group, 32a to 32n- Memory group, 34.
・27...Sampling pulse generation circuit, 35a to 35n・
...Switching circuit, 36...--Switching pulse generation circuit, 37...-OR gate,
38...and gate, 39 counter, 40...
...Decoder, 41-=Memo IJ-142...
...D/Ako/Nokuta. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure horizontal 5 lines 1) 0? Rectangle Figure 4 1.1 6H Figure 7

Claims (1)

[Claims] The screen on which the phosphor is coated is divided into a plurality of sections in the vertical direction, an electron beam is generated in each vertical section, and the electron beam is sequentially deflected in the vertical direction for each vertical section. A plurality of lines are displayed for each vertical section, and a plate-shaped conductor having an electron beam passage hole or slit is used as the electron beam path in the middle of the electron beam path from the electron beam generation source to the screen. The conductors are arranged so as to be orthogonal to each other, and a beam spot correction voltage having a waveform that changes as the electron beam is sequentially deflected in the vertical direction for each vertical section is applied to the conductor. Image 1 display device.