JPH0433242A - Image display device - Google Patents

Abstract

PURPOSE:To extend the period in which electron beams illuminate one phosphor and obtain high intensity on a screen by dividing a beam flow control back electrode controlling the quantity of the electron beams into multiple segments in the vertical direction. CONSTITUTION:Signals corresponding to video signals are applied to conducting plates 41a-41n and 41a'-41n' of a vertically divided electron beam flow control back electrode 41 to control the electron beams generated by linear cathodes 42a-42n and 42a'-42n', and the electron beams are extracted by a beam extracting electrode 3 and correctly separated for individual horizontal segments. The electron beams are electrostatically deflected horizontally and vertically by the potential difference applied between conducting plates 7a, 7b of a horizontal deflecting electrode 7 and conducting plates 8a, 8b of a vertical deflecting electrode 8. High voltage is applied to the metal-back layer of a screen 23, the electron beams are accelerated into high energy to collide with the metal- back layer, and phosphors 24 are illuminated.

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.
The present invention relates to a device that displays a plurality of lines by vertically deflecting each electron beam for each section to display an image as a whole.

2. Description of the Related Art The basic structure of a conventional image display device will be described with reference to FIG.

This display element includes, in order from the rear toward the anode side, an electron beam flow control back electrode 4, a line cathode 2 as a beam source,
A beam extraction electrode 3, a horizontal deflection electrode 7, a vertical deflection electrode 8, a screen plate IQ, etc. are arranged, and these are housed inside a vacuum container.

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.
A plurality of line cathodes 2 (fourth
In the figure, only four (2(a) to 2(d) are shown) are provided. In this embodiment, it is assumed that the spacing between the linear cathodes 2 is 3 mm and the number of linear cathodes 2 is 30.
(A) to 2 (M). Further, the distance between the line cathodes 2 cannot be freely increased, but is regulated by the distance between the vertical deflection electrode 8 and the screen 23 on the surface of the screen plate 8, which will be described later. As the configuration of these line cathodes 2, lO~30μ
An oxide cathode material is applied to the surface of the tungsten wire. As will be described later, the line cathodes 2 are controlled to sequentially emit electron beams from the upper line cathode 2 (a) to the lower line cathode 2 (ma) for a fixed period of time. The beam extraction electrode 3 has a large number of through holes 12 arranged at regular intervals in the horizontal direction facing each of the line cathodes 2 (a) to 2 (m), and allows the electron beam emitted from the line cathodes 2 to be passed through the beam extraction electrode 3 . It is taken out through the through hole 12.

The electron beam control back electrode 4 consists of conductive plates 4a to 4n formed horizontally divided into a plurality of parts on the inner surface of the glass plate 11, and these conductive plates 4a to 4n are connected to the beam extraction electrode 3.
The number of through holes 12 is 120 in this embodiment, and the amount of electron beams generated from the line cathode 2 corresponding to the picture elements of the video signal is determined by horizontal deflection, which will be described later. It is configured to be controlled in synchronization with the timing of Note that the glass plate 11 can be used in common with the glass plate serving as the substrate of the screen plate 10 in a glass container constituting a vacuum container.

The horizontal deflection electrode 7 is composed of a plurality of conductive plates 7a and 7b arranged vertically along both horizontal sides of the through hole 12 of the beam extraction electrode 3. A horizontal deflection voltage is applied to each pixel, and the electron beam for each picture element is deflected in the horizontal direction, and the R, G, and B phosphors are sequentially irradiated on the screen 23 to emit light. In this embodiment, each electron beam is deflected by two trios. The vertical deflection electrodes 8 include a plurality of conductive plates 8a and 8b arranged horizontally at vertically intermediate positions of the through holes 12 of the beam extraction electrodes 3.
A vertical deflection voltage is applied to deflect the electron beam in the vertical direction.

In this embodiment, the electron beam generated from one line cathode is deflected by eight lines in the vertical direction by a pair of conductive plates 8a and 8b. And vertical deflection electrode 8 composed of 31 pieces.
30 corresponding to each of the 30 line cathodes 2
Pairs of vertical deflection conductors are configured to draw 240 horizontal scanning lines on the screen 23 in the vertical direction.

As explained above, in this embodiment, a plurality of horizontal deflection electrodes 7 and a plurality of vertical deflection electrodes 8 are each arranged in a comb shape. Furthermore, by setting the distance to the screen 23 longer than the distance between the horizontal and vertical deflection electrodes,
It becomes possible to irradiate the screen 23 with the electron beam with a small amount of deflection. This allows the number of horizontal and vertical deflection electrodes to be reduced.

The screen 23 is constructed by coating the back surface of a glass plate, which is the substrate of the screen plate 10, with phosphor in stripes, and is also coated with a metal back and carbon, although not shown. The phosphor is the electron beam flow control back electrode 4
The conductive plate is designed to irradiate two trios of R, G, and B phosphor pairs by deflecting the main electron beam in the horizontal direction, and is coated vertically in stripes. ing.

In FIG. 4, the horizontal broken lines drawn on the screen 23 indicate the vertical divisions displayed corresponding to each of the plurality of line cathodes 2, and the one-dot chain lines indicate the plurality of electron beam flow control rear electrodes. 4 shows the horizontal divisions displayed corresponding to each of the four sections.

FIG. 5 shows an enlarged view of one section partitioned by these broken lines and dashed-dotted lines. As shown in Figure 5, in the horizontal direction 2
The trio of R, G, and B phosphors have a width of 8 lines in the vertical direction. In this embodiment, the size of one section is 1-1 in the horizontal direction and 30 in the vertical direction.

Although the phosphors of each of the three colors R, G, and H are shown in stripes in FIG. 5, they may be arranged in a delta pattern. However, when arranged in a delta shape, it is necessary to apply horizontal and vertical deflection waveforms that are compatible with the arrangement. Also,
In FIG. 5, for convenience of explanation, the aspect ratio is different from that of the image actually displayed on the screen.

Further, in this embodiment, R and G are applied to each of the conductive plates 4a to 4n of the electron beam flow control back electrode 4.

Although two trios of B phosphors are provided, it may be composed of one trio or more than three trios. However, one trio or more than three trios of R, G, and 'B video signals are sequentially arranged on the electron beam flow control back electrode 4, and it is necessary to perform horizontal deflection in synchronization with this.

Next, the operation of the drive circuit for driving this display element will be explained with reference to FIG. First, a driving portion that irradiates the screen 23 with an electron beam to display an image will be explained.

In FIG. 6, the power supply circuit 22 is a circuit for applying a predetermined bias voltage to each electrode of the display element, and applies a DC voltage of 3 to the beam extraction electrode 3 and V8 to the screen 23. The line cathode drive circuit 26 uses the vertical synchronization signal (1) and the horizontal synchronization signal H to create line cathode drive pulses (I-MA). The timing diagrams are shown in FIG. 7C and FIG. 8. As shown in Figure 8 (I to M), each line cathode 2 (A) to 2 (M) is heated by a current flowing while the drive pulse is at a high potential, and the drive pulse (I to M) is heated. A heated state is maintained to emit electrons during periods of low potential. As a result, electrons are emitted from the 30 line cathodes 2(a) to 2(ma) only during eight horizontal scanning periods to which low-potential drive pulses (i to ma) are applied, respectively. During the period when high potential is applied,
Line cathodes 2(a) to 2(ma) are lower than the potential around the line cathode 2 determined by the bias voltage applied to the electron beam control back electrode 4 and the beam extraction electrode 3.
Since the potential applied to the line cathode is higher, no electrons are emitted from the line cathode. To configure one screen, 8 lines are sequentially connected from the upper line cathode 2 (a) to the lower line cathode 2 (ma).
It is sufficient to switch the potential for each horizontal scanning period.

Next, the deflection portion will be explained. The deflection voltage generation circuit 40 is a direct memory access controller (hereinafter referred to as DMA).
controller) 411 Deflection voltage waveform storage memory (hereinafter referred to as deflection memory) 42, digital-to-analog converter (hereinafter referred to as D/A converter) 43h, 43v, etc., and vertical deflection signals v, v' and a horizontal deflection signal, h'.

In this embodiment, with regard to the vertical deflection signals v and v', in consideration of overscan, 24
0 horizontal scanning period is displayed. Further, the memory address area storing vertical deflection position information corresponding to each line is divided into a first field and a second field, each having one set of memory capacity. When displaying, data is read from the corresponding deflection memory 42, converted to an analog signal by the D/A converter 43v, and then sent to the vertical deflection electrode 8.
In addition to The vertical deflection position information stored in the deflection memory 42 is composed of almost regular data every 8 horizontal scanning periods, and the D/A converted waveform is also a vertical deflection signal with approximately 8 levels. , as mentioned above, has a memory capacity for two fields, so that the position can be finely adjusted for each horizontal scanning line.

Further, regarding the horizontal deflection signal, it is necessary to horizontally deflect the electron beam in six stages during one horizontal scanning period, and a memory is provided so that the deflection position can be finely adjusted for each horizontal scanning. Therefore, assuming that 480 horizontal scanning periods are displayed between one frame, 480x6 = 2880 bytes of memory are required, but since the data of the first field and the second field are shared, the memory is actually 1440 bytes. using memory. When displaying, the deflection information corresponding to each horizontal scanning line is read out from the deflection memory 42, converted into an analog signal by the D/A converter 43h, and then sent to the horizontal deflection electrode 7.
In addition to To summarize, a low-potential drive pulse of the line cathodes 2(a) to 2(ma) is applied during the display period excluding the vertical retrace period of the vertical period. The electron beam emitted from the line cathode is horizontally divided into 120 sections by the beam extraction electrode 3, forming 120 electron beam rows. As will be described later, the beam amount of this electron beam is controlled by the electron beam control back electrode 4 for each section, and as shown in FIG. R1, Gl, B1 and R2 of the screen 23 during each horizontal display period are
G2. The phosphors such as B2 are sequentially irradiated for each horizontal display period/6. (So each horizontal line has 12 rasters)
The electron beam is divided into R1, Gl, Bl and R2, G2 . By modulating with the video signal corresponding to B2, a color image can be displayed on the screen 23.

Next, the modulation control portion of the electron beam will be explained. First, in FIG. 6, signal input terminals 23R223G, 23
The R, G, and B video signals added to B are applied to 120 sample and hold circuits 31a to 31n. Each sample hold circuit 31a to 3]n is 6 for R1, Gl, Bl, and R2, G2, B2.
It consists of several sample and hold circuits. The sampling pulse generation circuit 34 has a horizontal period (63.5 μs)
During the horizontal display period (approximately 50 μs), 720 pixels corresponding to the sample-and-hold circuits for R1, Gl, and Bl, and for R2, G2, and B2 of the 120 sample-and-hold circuits 31a to 31n, respectively. pieces (120x6)
The sampling pulses Ral to Rn2 (FIG. 7A) are sequentially generated. Each of the 720 sampling pulses is connected to 120 sets of sample and hold circuits 31a to 31n.
As a result, each sample-and-hold circuit has R1, Gl, and Bl for each two picture elements when one line is divided into 120 parts.

R2, G2. Each B2 video signal is individually sampled and held. 120 sample-held pairs of R1, Gl, Bl, R2, G2. After the B2 video signal is sampled and held for one line, it is simultaneously transferred to 120 sets of memories 32a to 32n by a transfer pulse t (FIG. 7A), where it is held for the next one horizontal scanning period. The held signals are applied to 120 switching circuits 35a-35n. Switching circuit 35a
~35n are R1, G1. Bl, R2, G2.
B2 individual input terminals and a common pressure terminal that sequentially switches and outputs them, and receives switching pulses rl, gl, bl, r2 . R2゜b2 (7th
The switching is controlled at the same time by Figure B). Switching pulses rl, gl, bl.

r2. R2 and b2 divide each horizontal display period into six, and switch the switching circuits 35a to 35n for each horizontal display period/6 to time-divide and sequentially output each video signal of R1, Gl, Bl, R2, G2°B2. , pulse width modulation circuit 37a~
37n. Each switching circuit 35a-3
The output of 5n is applied to 120 sets of pulse width modulation (hereinafter referred to as PWM) circuits 37a to 37n, and R1, Gl, B
l, R2, G2. The pulse width is modulated according to the magnitude of each B2 video signal and output. This pulse width modulation circuit 37
The outputs of a to 37n are used as control signals for modulating the electron beam at 120 of the electron beam control back electrode 4 of the display element.
Each of the conductive plates 4a to 4n of the book is individually applied.

Next, horizontal deflection and display timing will be explained.

R1. in the switching circuits 35a to 35n. Gl,
Bl, R2, G2. B2 video signal switching and electron beams R1, Gl, Bl by the DMA controller 41, which is a horizontal deflection drive circuit.

R2, G2. The timing and order of switching the horizontal deflection to the B2 phosphor are synchronously controlled so that they completely match. As a result, when the R1 phosphor is irradiated with the electron beam, the irradiation amount of the electron beam is controlled by the R1 control signal, and the following Gl, Bl, R2, G2 . B2 is also controlled in the same way, and R1, Gl,
Bl, R2°G2. The light emission of each phosphor of B2 corresponds to the R1°Gl, Bl, 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.

Such control is executed for 120 sets (2 picture elements each) for 1 line for a period of time to display an image of 240 picture elements for 1 line, and then sequentially performed for 240 lines of 1 field starting from the upper line. An image is displayed on the screen 23. Further, the above operations are repeated for each field of the input video signal, and a television signal or the like is displayed on the screen 23.

The basic clock necessary for this embodiment is supplied from the pulse generation circuit 39 shown in FIG. 6, and the horizontal synchronization signal H
The timing is controlled by 1 and vertical synchronization signal ■.

Problems to be Solved by the Invention However, the above configuration has a problem in that the larger the screen is, the shorter the time period during which the electron beam is irradiated onto the phosphor, and the brightness of the screen is lowered.

The present invention solves the above problem by dividing the beam flow control back electrode in the vertical direction and simultaneously scanning multiple lines to increase the time that the electron beam irradiates one phosphor, thereby increasing the brightness of the screen. The object of the present invention is to provide an image display device with a high image quality.

Means for Solving the Problems In order to solve the above problems, the image display device of the present invention has a screen coated with a phosphor that emits light when irradiated with an electron beam, and a screen above the screen that is vertically divided. A line cathode that generates an electron beam in each vertical section, a deflection electrode that deflects the electron beam generated by the line cathode until it reaches the screen, and a line cathode that deflects the electron beam separated in each horizontal section. It is equipped with a plurality of electron beam flow control electrodes that are vertically divided to control the amount of light emitted from each picture element on the screen by controlling the amount of irradiation onto the screen.

Effects With the above configuration, the time for the electron beam to irradiate one phosphor on the screen is increased, making it possible to increase the brightness of the screen. However, it will be possible to achieve higher brightness.

Embodiment Hereinafter, an image display device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the electrode configuration of an image display device according to an embodiment of the present invention, and FIGS. 2 and 3 are block diagrams and waveform diagrams of various parts showing the basic drive circuit of the image display device, Components with the same numbers as the conventional example have the same configuration and functions.

In FIG. 1, 41 is an electron beam flow control back electrode, and its conductive plates are 41a to 41n and 41a' to 41.
It is divided into upper and lower parts like n' and is provided on the inner surface of a glass plate 11, which is a part of a glass container, for example, to control the amount of electron beam. 42 is a line cathode as an electron beam source, and there are a plurality of line cathodes at intervals in the vertical direction (42 in Fig. 1).
(a), 42(b) and 42(('), 42(o')
), and in this embodiment, the number is assumed to be 30 as in the conventional case, and the line cathode is connected to the electron beam flow control back electrode 4.
42(A) to 42( corresponding to the conductive plates 41a to 41n of
y) and 42 (i') corresponding to the conductive plates 41a' to 41n'.
) to 42 (yo).

In FIG. 2, 43 is a line cathode drive circuit, which uses a vertical synchronization signal V and a horizontal synchronization signal H to generate line cathode drive pulses (
Create (i~yo) and (i'~yo'). Figure 2 C,
D shows the timing diagram.

In this case, the difference from the conventional case is that each conductive plate 41a to 41n
and 41a to 41n', from the upper line cathode 2 (2(a') to the lower line cathode 2(E)
, 2 (Yo'), change the potential sequentially, 120
A total of 240 horizontal scanning lines are drawn for each book.

Regarding the image display device configured in this way, the following describes the first
The operation will be explained using the diagram and FIG.

In FIG. 1, electron beams generated from line cathodes 42(a) to 42C3) and 42(a') to 42(El') are transmitted to an electron beam flow control back electrode 41 which is divided into upper and lower parts.
The beam extraction electrode 3 extracts the electron beam and simultaneously separates it accurately into each horizontal section. Then, each electron beam is directed to the conductive plates 7a, 7 of the horizontal deflection electrode 7.
b and the electric potential difference applied between the conductive plates 8a and 8b of the vertical deflection electrode 8, the beam is electrostatically deflected horizontally and vertically. Further, a high voltage is applied to the metal back layer of the screen 23, and the electron beam is accelerated to high energy and collides with the metal back, causing the phosphor 24 to emit light.

In the basic drive circuit shown in FIG. 2, sample and hold circuits 31a to 31n and 31a' to 31n', memories 32a to 32n and 3
2a' to 32n', switches 35a to 35n and 3
5a' to 35n', PWM circuits 37a to 37n and 37a' to 37n' connect conductive plates 41a to 41n and 41a' to 4 of the electron beam flow control back electrode 41.
1n'(1n' in the drawing).
(Only the pairs are listed). R input to the basic drive circuit
The 9G and B video signals are sent to a sample hold circuit 31a controlled by a sampling pulse generation circuit 34.
~31n and 31a'~31n', then the memories 32a~32n and 32a'~32
n'. In this case, the memories 32a to 32n and 32a' to 32b are used, and the electron beam flow control back electrode 4 is divided into upper and lower parts.
The signals of the screen positions corresponding to the conductive plates 41a to 41n and 41a' to 41n of 1 are stored in memories 32a to 32n, respectively.
and 32a' to 32n', switch 35
a to 35n and 35a' to 35n, and are sent to PWM circuits 37a to 37n and 37a' to 37n', and are sent to conductive plates 41a to 41 of the electron beam flow control back electrode 41.
Separate signals are simultaneously applied to n and 41a to 41n'. Then, the electron beam flow control back electrode 41 is controlled by the line cathode drive pulses (I to YO) and (I' to YO') generated using the vertical synchronization signal V and the horizontal synchronization signal H in the line cathode drive circuit 43. The line cathodes corresponding to the conductive plates 41a to 41n and 41a' to 4In' respectively emit electrons, and after receiving horizontal and vertical deflection, two lines are emitted simultaneously on the top and bottom of the screen 23. It turns out.

Therefore, compared to the conventional method of vertically deflecting one screen one line at a time, this method of simultaneously vertically deflecting two lines at a time allows the electron beam to be applied to the screen for twice as long.
3, and if saturation of the phosphor is ignored, it is possible to display an image with twice the brightness of the conventional method.

In this embodiment, the beam flow control back electrode 41 is divided into two parts, upper and lower, but it may be further divided into a plurality of parts.

Effects of the Invention As described above, according to the present invention, by dividing the beam flow control back electrode that controls the amount of electron beam into a plurality of parts in the vertical direction, it becomes possible to irradiate a screen with a plurality of lines. Therefore, the time period during which the electron beam irradiates one phosphor of the screen becomes longer, and the brightness of the screen can be increased.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view showing the basic structure of an image display device in an embodiment of the present invention, FIGS. 2 and 3 are block diagrams and waveform diagrams of various parts showing the basic drive circuit diagram of the image display device, FIG. 4 is an exploded perspective view showing the basic structure of the conventional image display device, FIG. 5 is an enlarged view of the screen, and FIGS. 6 and 7 are block diagrams showing the basic drive circuit diagram of the conventional image display device. Waveform diagrams of various parts and FIG. 8 are timing diagrams of various waveforms. 3... Beam extraction electrode, 7... Horizontal deflection electrode,
8... Vertical deflection electrode, 23... Screen, 4I.
... Electron beam flow control back electrode, 42 ... Line cathode, 4
3...Line cathode drive circuit. Agent Yoshi Morimoto Hirokito Sagienha Figure ε Figure 2 2σ Figure S Figure 7

Claims (1)

[Claims] 1. A screen coated with a phosphor that emits light when irradiated with an electron beam, a line cathode that generates an electron beam in each vertical section of the screen above the screen, and an electron beam generated by the line cathode. separation means for separating the electron beam into each horizontal section and irradiating the screen onto the screen; and deflecting the beam in a plurality of steps in the vertical and horizontal directions up to the screen. a deflection electrode; and an electron beam flow control electrode for controlling the amount of emitted light of each pixel on the screen by controlling the amount of irradiation of the screen with the electron beam separated for each horizontal section, An image display device characterized in that an electron beam flow control back electrode is vertically divided.