JPS61181042A - Image display device - Google Patents

Abstract

PURPOSE:To increase luminance at least twice as much, by providing at least two electron beam sources in each of sections disposed in a vertical direction. CONSTITUTION:The density of electron beams is equivalently increased at least twice as much to heighten luminance. At least two electron beam sources are provided in each of sections disposed in a vertical direction. Since electric power for a linear cathode drive circuit to drive the sources is only changed by the number of the sources, the sources can be driven at conventional timing. Electron beams are emitted in parallel with each other from at least two electron beam sources in each section so that the current density appears to be increased at least twice as much. The quantity of electron beams reaching a faceplate is thus augmented to increase its luminance at least twice as much. This results in making it easy to make a visually powerful image.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention generates an electron beam for each division when a screen on a screen is vertically divided into a plurality of divisions, and generates an electron beam for each division. The present invention relates to an apparatus for displaying a plurality of lines by vertically deflecting a beam to display a television image as a whole.

Conventional technology 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 receive thin television images. It was impossible to create a machine. In addition, 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 display, and have not been put into practical use. It has not yet been reached.

Therefore, in order to achieve a flat display device using electron beams, the present applicant filed Japanese Patent Application No. 66-20618 (
A new display device was proposed in Japanese Patent No. 57-135690).

This method generates an electron beam for each section when the screen is vertically divided into multiple sections, and displays multiple lines by deflecting each electron beam vertically for each section. However, it displays a television image as a whole.

First, a basic configuration example of the image display element used here will be explained with reference to FIG. 2.

This display element is composed of a pole 5, a horizontal focusing electrode 6, a horizontal deflection electrode, a beam accelerating electrode 8, and a screen plate 9 arranged in order from the back to the front, and these are made of flat glass pulp ( (not shown) is housed in an evacuated interior.

A line cathode 2 serving as a beam source is stretched horizontally so as to generate an electron beam distributed linearly in the horizontal direction. (Only four wires, 2A to 22 are shown) are provided. In this embodiment, it is assumed that 16 pieces are provided. Let's call them 2i~2yo. These wire cathodes 2 are constructed by coating the surface of a tungsten wire with a diameter of 10 to 2 .mu..phi. with an oxide cathode material for thermionic emission.

These line cathodes 2A to 2Y are heated so as to generate a thermionic electron beam by passing an electric current through them, and as will be described later, the electron beams are generated sequentially for a certain period of time starting from the line cathode 2I. controlled to emit. The back electrode 1 suppresses generation of electron beams from line cathodes 2 other than the line cathode 2 that is controlled to emit electron beams for a certain period of time, and directs the generated electron beams only in the forward direction. It has the effect of pushing out. This back electrode 1 may be formed by a coating film of a conductive material adhered to the inner surface of the rear wall of the glass pulp. Furthermore, a planar electron beam emitting cathode may be used in place of the back electrode 1 and the line cathode 2.

It is a conductive plate 11 having a horizontally long slit 1o facing each of the vertical focusing electrode 3 wire cathodes 2a to 2mi, and the electron beam emitted from the wire cathode 2 is extracted through the entire slit 10, , vertically focused.

Electron beams for one horizontal line (360 pixels) are taken out at the same time.

In the figure, only one section in the horizontal direction is shown. 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 P1-like.

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',
Deflect the electron beam vertically. In this embodiment, the electron beam from one line cathode 2 is vertically deflected to a position corresponding to 16 lines by a pair of conductors 13, 13'. Then, 16 pairs of conductors corresponding to each of the 15 line cathodes 2 are formed by the 16 vertical deflection electrodes 4, and the electron beam is ultimately deflected to draw 240 horizontal lines on the screen e. do.

Next, the control electrodes 5 are composed of conductive plates 16 each having a vertically long slit 14, and a plurality of control electrodes 16 are arranged in parallel in the horizontal direction at predetermined intervals. In this embodiment, 180 conductive plates 15a to 15n for control electrodes are provided (only nine are shown in the figure). Each of the control electrodes 5 separates and extracts the electron beam into two picture elements in the horizontal direction, and controls the amount of electron beam passing therethrough in accordance with the video signal for displaying each picture element.

Therefore, if 180 conductive plates 15a to 15n for control electrode 6 are provided, 360 picture elements can be displayed per horizontal line. In order to display images in color, each picture element is displayed using phosphors of three colors R, G, and B, and each control electrode 5 has two picture elements worth of R, G, and B. Each video signal is applied sequentially.

In addition, 180 pairs of video signals for one line (2 pixels per pair) are simultaneously applied to each of the 180 conductive plates 15a to 15n for the control electrode 6, so that the video for one line is displayed at one time. Ru.

The horizontal focusing electrode 6 is composed of a conductive plate 17 having a plurality of vertically long slits 16 (180 slits) 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 electrodes 7 include a plurality of conductive plates 18.1 arranged vertically on both sides of the slit 16.
8', each electrode 18.18'
Six levels of horizontal deflection voltage are applied to the , and the electron beams for each picture element are deflected in the horizontal direction, so that two sets of R and G are displayed on the screen 9 .

Each of the phosphors B is sequentially irradiated to emit light. In this embodiment, the deflection range is two picture elements wide for each electron beam.

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 electron beam is accelerated to collide with the screen 9 with sufficient energy.

The screen 9 is constructed by applying a phosphor 20 that emits light when irradiated with an electron beam to the back surface of a glass plate 21, and adding a metal bank layer (not shown).

The phosphors 2o are provided with two pairs of phosphors of three colors R2G and H for each slit 14 of the control electrode 50, that is, for each one horizontally divided electron beam. It is applied in vertical stripes.

In FIG. 2, 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 6. Indicates the horizontal division displayed. As shown in an enlarged view in FIG. 3, one section partitioned by these two has R, G, and B phosphors 20 for two pixels in the horizontal direction.
It has a width of 16 lines in the vertical direction.

The size of one section is, for example, 1 in the horizontal direction and 9 in the vertical direction.

Note that in FIG. 2, the length in the horizontal direction is greatly expanded relative to the length in the vertical direction for clarity.

Furthermore, in this embodiment, only one pair of R, G, and B phosphors 2o are provided for one control electrode 6, that is, one electron beam, for two picture elements, but of course, one picture element The control electrode 6 may be provided with R, G, B for one picture element or three picture elements or more.
Video signals are applied sequentially, and horizontal deflection is performed in synchronization with the video signals.

Next, the basic configuration of a drive circuit for displaying television images on this display element will be described with reference to FIG. 4. First, a driving portion for irradiating the screen 9 with an electron beam to cause the raster to emit light will be described.

The power supply circuit 22 is a circuit for applying a predetermined bias voltage (operating voltage) to each electrode of the display element, -1 to the back electrode 1, and 3 to the vertical focusing electrode 3, 3'. DC voltages (2)3', (26) to the horizontal focusing electrode 6, (28) to the accelerating electrode 8, and (3)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.

Vertical deflection drive circuit 40, vertical deflection counter 25.
Memory 27 for vertical deflection signal storage. It is constituted by a digital-to-analog converter 39 (hereinafter referred to as a DA converter). The input pulse of the vertical deflection drive circuit 4o is as follows:
A vertical synchronizing signal (2) and a horizontal synchronizing signal (H) shown in FIG. 6 are used. The vertical deflection counter 26 (8 pits) is reset by the vertical synchronizing signal V and counts the horizontal synchronizing signal H. This vertical deflection counter 25 is counted during an effective scanning period (in this case, 24
This count output is supplied to the address of the memory 27. Vertical deflection signal data (here, 10 bits) corresponding to each address is output from the memory 27, and is converted to V as shown in FIG. 5 by the DA converter 39.

V' is converted into a vertical deflection signal. In this circuit 240
There is a memory address for storing a vertical deflection signal corresponding to each line of H minutes, and by storing regular data in the memory every 1 eH minutes, 16 levels of vertical deflection signals can be obtained.

On the other hand, the line cathode drive circuit 26 generates a line cathode drive pulse [
I~Yo]. FIG. 6(a) shows the vertical synchronization signal V,
The relationship between the horizontal synchronizing signal H and the lower 6 bits of the vertical deflection counter 26 is shown.

FIG. 6(b) shows a method of creating line cathode drive pulses [A' to Y'] every 16H using these signals.

In Figure 6, LSB indicates the lowest pit, (LSB+1)
means the bit one higher than the LSB.

The first line cathode drive pulse [A'] is the vertical synchronization signal V
and the output (LSB+4) of the vertical deflection counter 26 can be used to generate the line cathode drive pulses using a shift register. [A'] can be obtained by transferring the inverted output (I, SB+3) of the vertical deflection counter 26 as a clock. This drive pulse [A' to Yo'] is inverted and converted into a line cathode drive pulse [I to Yo], which has a low potential only during each pulse period, and a high potential of about 20 volts during other periods. , are added to each line cathode 2i to 2yo.

Each line cathode 2i to 2yo is heated by a current flowing through it during the high potential of the driving pulse [i to yo].
The heated state is maintained so that electrons can be emitted during the low potential period (I to Y). As a result, 15 line cathodes 2-2
From Y to Y, electrons are emitted only during the 16H period when a low potential drive pulse [I to Y] is applied to each of them. During the period when a high potential is applied, the back electrode 1 and the vertical focusing electrode 3
Since the high potential applied to the linear cathodes 2i to 2yo is more positive than the potential at the position of the linear cathodes 2 determined by the bias voltage applied to the linear cathodes 2i to 2yo, No electrons are emitted from yo. 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 pushed forward by the back electrode 1, pass through the opposing slits 1Q of the vertical focusing electrode 3, and are focused in the vertical direction to form a flat electron beam.

Next, the line cathode, drive pulse [I to Y] and vertical deflection signal v
, v' will be explained using FIG.

Vertical deflection signals V, V' are one of each line cathode pulse [I to Y]
During the 6H period, it changes in steps of 1H and changes in 16 steps. The vertical deflection signals V and V' both have a center voltage of 4, and are configured to change in opposite directions so that V increases sequentially and V' decreases sequentially. These vertical deflection signals V and V' are applied to the electrodes 13 and 13' of the vertical deflection electrode 4, respectively, and as a result, the electron beams generated from the respective line cathodes 2I to 2Y are directed vertically by 16
It is deflected into stages, and as mentioned earlier, on the screen it is 1
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 each 16H period from the top of the 16 line cathodes 2I to 2Y, and each electron beam is sequentially emitted for one line from top to bottom within 15 sections in the vertical direction. As a result, the electron beam is vertically deflected one line at a time on the screen 9 from the first line at the top end to the 240th line at the bottom end, thereby drawing a raster of 240 lines in total.

The electron beam thus vertically deflected is horizontally divided into 180 sections by the control electrode 5 and the horizontal focusing electrode 6 and extracted. Figure 2 shows one of these categories. The amount of electron beam passing through each section is controlled by a control electrode 5, and is focused horizontally by a horizontal focusing electrode 6 into a single narrow electron beam.
The light is deflected horizontally in six steps by the horizontal deflection means described below, and is sequentially irradiated onto the R, G, and B alloy light bodies 20 corresponding to two picture elements on the screen 9. FIG. 3 shows the vertical and horizontal divisions. 158 to 15 of each of the control electrodes 5
The phosphors corresponding to n are R, G, and B for two picture elements, but for convenience of explanation, one picture element is R1, G1, . B, and the other R2
, G2. B2.Next, the horizontal deflection drive circuit 41 is composed of a horizontal deflection counter (11 bits), a memory 29 storing a horizontal deflection signal, and a DA converter 38. The input pulses of the horizontal deflection drive circuit 41 are a vertical synchronizing signal ■ and a horizontal synchronizing signal H, as shown in FIG.
A pulse 6H with a repetition frequency six times that of the horizontal synchronizing signal H is used.

The horizontal deflection counter 28 is reset by the vertical synchronizing signal V and counts the horizontal six-fold pulse 6H. This horizontal deflection counter 28 counts 6 times during 1H and 240Hx6/H=1440 times during 12, and this count output is supplied to the address of the memory 29. From the memory 29, horizontal deflection signal data (
Here, 8 bits) are output, and the D-A converter 38 outputs the
As shown in FIG. 8, it is converted into a horizontal deflection signal such as h/.

This circuit has memory addresses for storing horizontal deflection signals corresponding to each of 6 x 240 lines, and by storing 6 pieces of regular data for each line in the memory, 6-step horizontal waves are generated in 1H period. A deflection signal can be obtained.

As shown in Fig. 8, this horizontal deflection signal is a pair of horizontal deflection signals ri and h' that change in 6 steps, both of which have a center voltage of 7, where h decreases sequentially and h' increases sequentially. As they progress, they change in opposite directions. These horizontal deflection signals, h/, are electrodes 18 and 1 of the horizontal deflection electrode 7, respectively.
8' is added. As a result, each horizontally divided electron beam is transmitted to the R, G of the screen 9 during each horizontal period.
.

B, R, G, B (R1, G1.B1.R2,
G2. It is horizontally deflected so that the phosphor B2) is sequentially irradiated with H/6. Thus, in each line raster, the electron beam is R1 for each of the 180 sections in the horizontal direction.
, G1. B1. R2, G2. Each phosphor 20 of B2 is sequentially irradiated.

Therefore, the electron beam is set to R1, G for each horizontal section of each line.
1. B1. R2, G2. By modulating with the B2 video signal, 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, 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 R, G, and B). (referred to as a video signal) is output. These R, G, and B video signals are processed by 180 sample and hold circuit sets 31a to 31.
It is added to n. Each sample and hold circuit set 31a to 3
1n is for R1, G1, B1, R2, G2 respectively
It has 6 sample and hold circuits for 1 and B2. These sample and hold outputs are respectively applied to holding memory sets 32a-32n.

On the other hand, the reference clock oscillator 33 is composed of a PLL (phase-locked loop) circuit, etc., and in this embodiment generates a reference clock 6f8C that is six times the color subcarrier f8C and a reference clock fSC that is twice the color subcarrier f8C. The clock is controlled to always have a constant phase with respect to the horizontal synchronization signal H.The reference clock 2fso is applied to the deflection pulse generation circuit 42, and
Double signal 6H and - every signal switching pulse r1. q1. b
1. r2°G2. I am getting a B2 pulse. On the other hand, the reference clock 6fSC 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 horizontal period (63,5μ5ec)
1 during the effective horizontal scanning period (approximately 50μ5ec)
080 sampling pulses Ra1 to Bn2 are sequentially generated, and then one transfer pulse t is generated. These sampling pulses Ra1 to Bn2 correspond to each picture element when one line of the video to be displayed is divided into 360 picture elements in the horizontal direction, and their positions are always constant with respect to the horizontal synchronizing signal H. controlled by.

These 1080 sampling pulses Raj~Bn2 are applied to 180 sample hold circuit sets 31a~3, respectively.
1n, and as a result, each sample-and-hold circuit set 31a to 31n has R1, G1 . B1.
R2, G2. Each video signal of B2 is individually sampled and held.

180 pairs of R1, G, which were sampled and held.

B1. R2, G2. The video signal of B2 is stored in 180 sets of memories 32a to 32n after sample and hold for one line is completed.
are transferred all at once by a transfer pulse t, and are held here for the next horizontal period. These R1, G1.
B1. R2, G2. The signal of B2 is the switching circuit 3
Added to 5a-35H. Switching circuit 35a~
36n is R1, G1°B1. R2, G2. B2
It is composed of a tri-state or analog gate having individual input terminals and a common output terminal for sequentially switching and outputting these input terminals.

The output of each switching circuit 35a-35n is applied to 180 sets of pulse width modulation (PWM) circuits 37a-37n, where sampled and held R, , G1 . B1.
R2, G2. B2 The reference pulse signal is pulse width modulated in accordance with the magnitude of the video signal and is output. The repetition period of the reference pulse signal is the signal switching pulse r1.
g1. b1. r2, g2.

It is desirable that the pulse width be sufficiently smaller than the pulse width of B2, and for example, a pulse width of about 1:10 to 1:100 is used.

The outputs of the pulse width modulation circuits 37a to 37n are individually applied to the 180 conductive plates 15a to 15n of the control electrode 5 of the display element as control signals for modulating the electron beam. Each switch 77 circuit 35a to 35m receives a switching pulse r1 +'J1 lB1, r21 (J2 l
Switching is controlled simultaneously by B2. The switching pulse generation circuit 36 receives the signal switching pulse r1 +'J1 lB1 + r2+ from the aforementioned deflection pulse generation circuit 42.
92+b2, each horizontal period is divided into six, and the switching circuits 35a to 35n are switched by H/e, R,, G,.

B1. R2, G2. The switching signals r1 +q1, bl, r2 . g2. B2
occurs.

What should be noted here is that the switching circuit 35a-3
R1.5n. G1. B1. R2, G2°B2 video signal supply switching, horizontal deflection, and electron beam R1, G1 . B1. The horizontal deflection of R2, G2 and B2 for switching the irradiation to the phosphor is synchronously controlled so that they completely match both in timing and order. As a result, when the electron beam is irradiating the R1 phosphor, the irradiation amount of the electron beam is R1.
G1. B1. R2, G2.
B2 is also controlled in the same way, and R1 and G1 of each picture element
．． B1. R2゜GB The light emission of each phosphor is the R of that picture element.
1.G.

2ν 2 B1. R2, G2. Each picture element is controlled by the B2 video signal, and each picture element is displayed by emitting light according to the input video signal. This control is for one line.
This is done simultaneously for 80 sets (2 picture elements each) to display an image of 360 pixels per line, and then for 240 minutes of lines sequentially starting from the upper line, so that one image is displayed on the screen 9. It becomes K.

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.

Problems to be Solved by the Invention In the above image display device, the rate of arrival of the electron beam generated from the electron beam source to the screen surface (effective utilization rate of the electron beam) is approximately 2° to 3°, which is The effective beam utilization rate is comparable to that of the shadow mask of the decentralized line tube. Therefore, since this image display device has a high voltage of about 10 KV compared to the current cathode ray tube's high voltage of 20 KV (size), if the current density is about the same, the brightness will only be about %. As a result, there are problems in that the brightness is not suitable for practical use, the dynamic range is small, and the screen is unimpressive.

On the other hand, if the high voltage is increased to about 20 KV, the brightness will be comparable to that of current cathode ray tubes, but this will require a considerable distance between the high voltage electrode and other electrodes in order to satisfy the dielectric strength. Therefore, the advantage of being thinner is lost.

Means for Solving the Problems Therefore, in the present invention, the brightness is increased by doubling or more the density of the electron beam equimetrically. That is, at least two or more electron beam sources are provided for each section in the vertical direction. The line cathode drive circuit that drives this can drive these electron beam sources at the conventional timing by simply changing the power accordingly.

Effect: Electron beams are generated in parallel from two or more electron beam sources in each vertical section, and it is as if the current density has more than doubled, increasing the amount of electron beams reaching the screen surface and reducing the brightness by 2. It can be increased more than twice.

Example FIG. 1 shows an electron beam source portion of an embodiment of the present invention.

10o is the back electrode, 101 is the vertical focusing electrode, 102 is 2
A book electron beam source (an example of a line cathode) is shown, and 103 is a conventional one, 7j/I<5 aydA image.

The other electric $i configurations and drive circuits have exactly the same configuration.

Effects of the Invention In this way, by doubling the electron beam density or more, it is possible to more than double the brightness and obtain powerful images with a high dynamic range without increasing high voltage. easily possible.

[Brief explanation of drawings]

FIG. 1 is a sectional view of essential parts of an image display device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view showing the basic electrode configuration of the image display device to which the present invention is applied, and FIG. 3 is a screen thereof. 4 is a block diagram of the drive circuit in the above image display device, FIG. 5 is a waveform diagram showing the correlation between the vertical deflection voltage and the horizontal synchronizing signal, and FIG. Figure 6. FIG. 7 is a waveform diagram showing the relationship among the cathode drive pulse, vertical deflection signal, and horizontal deflection signal, and FIG. 8 is a waveform diagram showing the correlation between the horizontal deflection voltage and the horizontal synchronizing signal. 1.100...Back electrode, 2,2i-22. 102... Line cathode (a cathode), 4...
... Vertical deflection electrode, 5 ... Beam flow control electrode,
7... Horizontal deflection electrode, 9... Screen, 1o... Slit, 20... Fluorescent material. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 5 Figure 6 C) LSD 4'
/IH(bnnyo・; Figure 8

Claims (1)

[Claims] a screen coated with a phosphor that emits light when irradiated with an electron beam; an electron beam source that generates an electron beam for each vertical division of the screen on the screen; separation means for separating the electron beam generated by the electron beam source into each horizontal section and irradiating the screen; a beam flow control electrode that controls the amount of light emitted from each pixel on the screen by controlling the amount of electron beams separated into the horizontal sections irradiated onto the screen; , a focusing electrode that controls the size of light emitted by the electron beam on the phosphor surface in each pixel, a back electrode that controls the amount of electron beam from the electron beam source, and an electron beam that accelerates the electron beam to the screen. In addition to being equipped with an accelerating electrode for irradiating,
An image display device characterized in that at least two electron beam sources are provided in each of the plurality of vertical sections divided in the vertical direction.