JPS6115195A - Driving of image display unit - 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 (Field of Industrial Application) The present invention relates to a method for driving a flat panel image display device.

(Structure of a conventional example and its problems) An example of a basic structure of a conventional image display device and its driving method will be explained with reference to FIG. This display device consists of a back electrode 1, a line cathode 2 as a beam source, a vertical focusing electrode 3.3', a vertical deflection electrode 4, a beam current control electrode 5, a horizontal focusing electrode 6, a horizontal focusing electrode 6, and a horizontal deflection electrode 3, 3', a vertical deflection electrode 4, a beam current control electrode 5, a horizontal focusing electrode 6, and a horizontal deflection electrode 3. It consists of an electrode 7, a beam accelerating electrode 8, and a screen 9, which are housed in the evacuated interior of a flat glass globe (not shown).

The line cathode 2 as a beam source is stretched in the horizontal direction so as to generate an electron beam distributed linearly in the horizontal direction, and a plurality of line cathodes 2 are arranged vertically at appropriate intervals. (shows only four pieces, 2a1 to 2d1)
It is provided. In this embodiment, it is assumed that 15 pieces are provided (assumed to be 23 degrees 2 degrees). These line cathodes 2
For example, it is constructed by coating an oxide cathode material on the surface of a tungsten wire with a diameter of 10 to 20 μΦ. Then, as will be described later, the electron beams are controlled to be emitted sequentially from the upper line cathode 2a1 for a fixed period of time. Back electrode 1
has the effect of suppressing the generation of electron beams from other line cathodes 2 other than the line cathode 2 that is controlled to emit electron beams for a certain period of time, and pushing out the generated electron beams only in the forward direction. do.

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.

The vertical focusing electrode 3 has a horizontally long strip facing each of the line cathodes 2a1 to 2o1. jy) 10, which takes out the electron beam emitted from the line cathode 2 through its slit 10 and focuses it in the vertical direction (the slit 10 may have bars provided at appropriate intervals in the middle). (It is a row of through holes arranged in large numbers at small intervals in the horizontal direction, or at intervals such that they almost touch each other, and may be substantially configured as slits.)

The vertical focusing electrode 3' is also similar.

A plurality of vertical deflection electrodes 4 are arranged horizontally at intermediate positions of the slits 10, and conductors 13, 13' are provided on the upper and lower surfaces of the insulating substrate 12, respectively.
It consists of a set of A vertical deflection voltage is applied between the opposing conductors] 3 and 13' to deflect the electron beam in the vertical direction. In this embodiment, a pair of conductors 13 and 13' deflect the electron beam from one line cathode 2 to positions corresponding to 16 lines in the vertical direction.

And 15 line cathodes 2 are formed by 16 vertical deflection electrodes 4.
15 pairs of conductors corresponding to each one are constructed, and the electron beam is deflected so as to draw 240 horizontal lines on the screen 9.

Next, the control electrodes 5 (each of which divides the electron beam horizontally into one pixel and extracts it, and displays the amount of electron beam passing through it as an image for displaying each pixel). Each conductive plate 15 has a long slit 14 in the vertical direction, and a plurality of conductive plates 15 are arranged in parallel in the horizontal direction at predetermined intervals.

In this embodiment, 320 control electrode conductive plates 15a to 1
5ri are provided (only 10 are shown in the figure).

Therefore, if 32,020 control electrodes 5 are provided, 320 picture elements can be displayed per 1 horizontal line/minute.

In addition, in order to display images in color, each picture element is R, G.
, B, 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 has a plurality of vertically long slits 16 (320 slits) facing the slits 14 of the control electrode 5.
It is composed of a conductive plate 17 having a conductive plate 17, and focuses the electron beams of each picture element divided horizontally into a narrow electron beam in the horizontal direction.

The horizontal deflection electrodes 7 include a pair of conductive plates 18 arranged vertically at respective positions of the slits 16;
18', each conductive plate 18 and 18
A horizontal deflection voltage is applied between '' to horizontally deflect the electron beam of each picture element, and sequentially irradiate each of the R, G, and B phosphors on the screen 9 to cause them to emit light. Make it. In this embodiment, the deflection range is the width of one pixel for each electron beam.

The accelerating electrode 8 is composed of a plurality of conductive plates 9 arranged horizontally at the same position as the vertical deflection electrode 4, and accelerates the electron beam so that it collides with the screen 9 with sufficient energy. .

The screen 9 is constructed by coating the back surface of a glass plate 2 with a phosphor 20 that emits light when irradiated with an electron beam, and adding a metal back layer (not shown).

The phosphor 20 is arranged at R for one slit 14 of the control electrode 5, ie for each horizontally divided electron beam.

A pair of phosphors of three colors, G and B, are provided, and are applied vertically in a striped pattern. 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. 1 divided by these two
As shown in an enlarged view in Figure 2, each section has R, G, and B phosphors 20 for one pixel in the horizontal direction, and has a width of 16 lines in the vertical direction. . The size of one section is, for example, 1 column in the horizontal direction and 16 columns in the vertical direction.

Note that in FIG. 1, the length in the horizontal direction is drawn very far out from the vertical direction to make it easier to understand.

In addition, in this embodiment, only one pair of R, G, and H phosphors 20 for one picture element is provided for one control electrode 5, 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 5, and the horizontal deflection is synchronously applied to the control electrode 5. It will be done.

Next, problems with the conventional example will be explained. When performing a color display using the above-mentioned image display device, in order to obtain white color by combining the luminescence of the R2O and B phosphors, the electron beam current irradiated to the R, G, and B6 phosphors must be It is necessary to set the ratio determined by the luminous efficiency of the body, etc. Conventionally, by controlling the electron beam with the control electrode 5, υR, G, B
The ratio of electron beam current irradiated to each phosphor was set. That is, R, G applied sequentially to the control electrode 5
, B6 video signals were weighted for each color.

On the other hand, the maximum value of the electron beam current is a value determined by the configuration of the image display device, etc. Therefore, the ratio of the electron beam currents irradiated to the R, G, and B6 phosphors is determined when the ratio of the electron beam currents is the maximum. The electron beam current irradiated to the other two phosphors was limited to the electron beam current irradiated to the phosphor. Therefore, the electron beam utilization rate decreases due to an unbalance in the ratio of electron beam currents irradiated to the R, G, and B6 phosphors, and the maximum brightness of white color is due to the maximum ratio of electron beam currents (low luminous efficiency). This is determined by the phosphor, and this has been a major problem in terms of improving the brightness of image display devices and selecting phosphor materials.

(Object of the Invention) The present invention solves the above-mentioned conventional problems, and aims to solve the above-mentioned problems of the conventional technology.
An object of the present invention is to provide a method for driving an image display device that allows setting the ratio of the amount of light emitted from a phosphor.

(Structure of the Invention) The present invention provides an image in which the ratio of the amount of light emitted from the R2O and B6 phosphors is changed depending on the time-sharing ratio of electron beams that are sequentially irradiated to each of the R, G, and B phosphors in a time-sharing manner. This is a method for driving a display device, and it is possible to change the ratio of the amount of light emitted by the R, G, and B6 phosphors without reducing the utilization rate of the electron beam.

(Description of Embodiments) As a specific embodiment of the image display device of the present invention, a case where a television video is displayed on the image display device will be described. First, the image display device used here has exactly the same configuration as the conventional example shown in FIG. R, G, B6 phosphor materials include R: Z n S e : Cu, G :
Zn25in4: Mn XB: ZnS; Ag
, Cu was used. In order to obtain white color by combining these light emissions, the electron beam current 1 applied to the R1 and B6 phosphors is
．． ,I. The ratio of ,■, is 43:38:19.

Next, a method for displaying television images on this image display device will be explained using FIG. 3. FIG. 3 shows the basic configuration of the drive circuit of the image display device. First, a driving portion for irradiating the screen 9 with an electron beam to emit raster 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, -V1 to the back electrode 1, V to the vertical focusing electrode 3.3'.

■3', V6 for horizontal focusing electrode 6, V8 for accelerating electrode 3
・Apply the DC voltage of ■9 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/response generating circuit 25 is composed of a counter that is reset by a vertical pulse and counts the horizontal nof pulse, and is configured to cover an effective vertical scanning period (in this case, 240H) excluding the vertical retrace period of the vertical period. 15 drive pulses a each having a length of 16H period
j, bl, ・01 are generated. The driving noculus aj, t, +, . Linear cathode drive/grease brought to potential a'1. b′1
．． ... o'j, and each line cathode 28, , 2
b, ,・Added to 2o+.Each line cathode 2a1...
・2゜1 is heated by passing a current between the high potentials of its driving contacts a'1 to o'1, and the driving contact ξ is heated.
The heated state is maintained so that electrons can be emitted even during the low potential period of 1 to o/+. As a result, 15 wire cathodes 2a
From 1 to 2o1, low potential drive/e) response a
Electrons are emitted only during the 16H period when '1 to 0'1 are applied (during the period when a high potential is applied, the electrons are Since the potential applied to the linear cathodes 2a, 2o, is higher than the potential at the position of the linear cathodes 2, electrons are not emitted from the linear cathodes 2a1 to 2o1). Thus, in the line cathode 2, during the effective vertical scanning period, the upper line cathode 23. Line cathode below 20. Electrons are emitted every 18H period in the order of °C.

The emitted electrons are pushed forward by the grooved electrode 1, pass through the opposing slits IO of the vertical focusing electrode 3, and are vertically focused into a flat electron beam.

Next, the vertical deflection drive circuit 27 generates vertical drive pulses a1 to 0.
It consists of a counter that counts horizontal synchronizing signals reset by each of 1 and a conversion circuit that converts the count output to D/A, and
A pair of vertical deflection signals v and v' that change in 16 steps by IH are generated during a 16H period of signals a1 to 01. The vertical deflection signals V and V' both have a center voltage of v4, and are configured to change in opposite directions so that (2) increases sequentially and V' decreases sequentially. These vertical deflection signals V and V' are applied to the conductors 13 and 13' of the vertical deflection electrode 4, respectively, and as a result, the electron beams generated from the respective line cathodes 2a, ~2o1 are deflected in 16 steps in the vertical direction. As described above, one electron beam is deflected on the screen 9 so that a raster of 16 lines is drawn one line at a time from the top.

As a result of the above, electron beams are emitted sequentially from above the 15 line cathodes 2a1 to 2o1 for 16H periods, and each electron beam is deflected by one line from above to below 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, and a total of 240 raster lines are drawn.

The electron beam thus vertically deflected is divided into 320 sections in the horizontal direction by the control electrode 5 and the horizontal focusing electrode 6 and extracted. Figure 1 shows one of these categories. The amount of electron beam passing through each section is controlled by a control electrode 5, and is horizontally focused by a horizontal focusing electrode 6 into a single thin electron beam. The effective horizontal deflection period is the electron beam current II+ for obtaining white light by combining the light emissions of the R, G, and B phosphors.
(i l Almost the same ratio as the ratio of 1B (here /1
3:38:19) and is deflected in three stages to sequentially irradiate each of the R, G, and H phosphors 20 on the screen 9. That is, the horizontal drive/glare generation circuit 28 is composed of three monostable multi-pie breaks connected in cascade, etc., and the electron beam current IRI16. Three groups r, g, and b'i are generated, each having a width approximately equal to that of IB. Here - as an example, we set each pulse width to 215μ
sec, 19μsec, 9.5μSee, three /? during the effective horizontal scanning period of 50μsec. Luz r+
g+t) is generated.

These horizontal drive pulses (r+g+k) are applied to the horizontal deflection drive circuit 29. This horizontal deflection drive circuit 29 is switched by horizontal drive reference j+grb and
A pair of step-varying horizontal deflection signals 1 and h' are generated.

The horizontal deflection signals h 1 and h' both have a center voltage of v7, and change in opposite directions such that h sequentially increases and h' sequentially decreases. These horizontal deflection signals, t/
are applied to the conductive plates 18 and 18' of the horizontal deflection electrode 7, respectively. As a result, each horizontally segmented electron beam sequentially hits the R, G, B6 phosphors of the screen 9 for 21.511 seconds during each horizontal period.

It is horizontally deflected so that it is irradiated for 19 μsec + 9.5 μsec.

Thus, in each raster line, the electron beam is sequentially irradiated onto each of the RlG and B phosphors 20 in each of the 320 horizontal sections. Therefore, R and G electron beams are applied to each horizontal section of each line.

By modulating with the B 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
The color difference signals of (referred to as a video signal) is output. Sample bold circuit set 31 for those R, G, and B6 video signals Vi320 sets. a
~31 n VC added. Each sample-and-hold circuit set 31a to 31n has three sample-and-hold circuits for R, G, and B, respectively. The Sansol hold outputs of these Sansol hold circuit sets 31a to 31n are applied to holding memory groups 32a to 32n, respectively.

On the other hand, the reference clock oscillator for sunsilling 33dPLL
(Phase-Lock Druzot) circuit, etc., and in this embodiment generates a reference tarock of approximately 6.4 MHz. 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 signal generating circuit 34, where it is delayed by one clock period by a soft reno star, etc., for an effective horizontal scanning period (approximately 50 μS) of the horizontal period (635 μs). to 32
0 scanning pulses a ''-n are generated in sequence, followed by one transfer pulse. This scanning pulse a ''-n horizontally moves one line of the image to be displayed. It corresponds to each picture element when divided into 320 picture elements in the direction, and its position is controlled so as to be always constant with respect to the horizontal synchronizing signal [1].

These 320 sampling circuits a-n correspond to the 320 sample hold circuit sets 31a to 3, respectively.
As a result, the R, G, and B video signals of each picture element when one line is divided into 320 picture elements are individually sampled and held in each sample hold circuit set 31a to 31n. be done. The 320 sets of R, G, and B video signals subjected to the sensor hold are transferred to the memory 32 of 320 sets after the sensor hold for one line is completed.
A to 32n are transferred all at once by a transfer pulse t, and held here for the next one horizontal period.

One line of R, G stored in the memories 32a to 32n
, B video signals each have 320 switching circuits 3.
Added to 5a-35n. Switching circuit 35a~
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. The switching circuits 35a to 35n are simultaneously switched and controlled by the switching pulses added to the switching pulse generating circuit 36. Sui, Chingturus generation circuit 3
6 is controlled by the pulses r, g, and b from the horizontal driving pulse generating circuit 28 mentioned above, and the switching circuits 35a to 35n are switched by dividing the center portion of each horizontal period into three parts of about 50μ5eci and switching the switching circuits 35a to 35n at intervals of about 17μsee. ,R,G,
Each video signal of B is time-divided and outputted alternately and sequentially, and switching signals r, g, and b are generated so as to be supplied to the conductive plates 15a to 15n of the control power 5.

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 B are similarly controlled, so that the R, G, and B6 of each picture element are controlled in the same way. The light emission of the phosphor is controlled by the R, G, and B video signals of the picture element, so that each picture element is displayed by emitting light according to the input video signal. Such control is performed simultaneously on 320 picture elements for one line to display one image, and then sequentially for 240 lines starting from the upper line, so that one image is displayed on the screen 9. will be displayed.

The above-mentioned operations are performed on one part of the input television signal.
This is repeated for each field, and as a result, a moving TV image is projected on the screen 9, similar to a normal TV receiver.

The method for driving the image display device of this embodiment described above includes R, G,
R, G to obtain white color by combining the luminescence of B6 phosphor
, B6 Setting the ratio of light emission amount of the phosphor iR, G , B6
It is determined by the current density of the electron beam irradiated to the phosphors (R, G, B6), but by the electron beam irradiation time to the phosphors, that is, the light emission time of each phosphor, and the effective horizontal scanning period (for example, 50μSee) to R, G, B6
R,
G.

By irradiating the B6 phosphor with an electron beam and synchronously switching the video signals of R, G, and B colors applied to the control electrode 5, white can be synthesized without reducing the utilization rate of the electron beam. can.

Furthermore, by adjusting the time division ratio of the effective horizontal scanning period, it is possible to adjust the chromaticity of the white color obtained by combining the light emissions of the R, G, and B6 phosphors.

In addition, the ratio of the electron beam current applied to the R, G, and B6 phosphors to obtain white light is not a problem, and depending on the purpose of improving brightness or expanding the color reproduction range, It is also possible to select and combine a wide range of R, G, and B6 phosphor materials.

(Effect of the invention) The driving method of the image display device of the present invention is R, G.

R, G depending on the ratio of electron beam irradiation time to B6 phosphor
, which changes the ratio of the amount of light emitted by the B6 phosphor,
White light can be synthesized without reducing the utilization rate of the electron beam, and the implementation effect is significant.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of an image display device, FIG. 2 is an enlarged view of a main part of a phosphor film on a screen in the same device, and FIG. 3 is a diagram illustrating a driving method of an image display device of the present invention. FIG. 2 is a basic configuration diagram of a drive circuit that is beyond description. DESCRIPTION OF SYMBOLS 1... Back electrode, 2... Line cathode, 3, 3'... Vertical focusing electrode, 4... Vertical deflection electrode (electron beam deflection means), 5... Beam flow control electrode (electron beam control means), 6... horizontal focusing electrode, 7... horizontal deflection electrode, 8
...Beam accelerating electrode, 9...Screen (light emitting means)
, 1°...Slit, 11...Conductive plate, 12...
Insulating substrate, 13, 13'... Conductor, 14... Slit l-115... Conductive plate, 16... Slit, 17,
18.19... Conductive plate, 20... Fluorescent material, 22...
Power supply circuit, 23... Input terminal, 24... Synchronization separation circuit, 25... Vertical drive pulse generation circuit, 26... Line cathode drive circuit, 27... Vertical deflection drive circuit, 28...
・Horizontal drive/Guru generation circuit, 29 ・Horizontal deflection drive circuit, 30 Color demodulation circuit, 31a to 3In... Sample hold circuit, 32a to 32n... Memory, 33...
Sampling reference clock oscillator, 34... Sampling pulse generation circuit, 35a to 35n... Switching circuit, 36... Switching pulse generation circuit. Figure 2! Ward f Figure 3

Claims (3)

[Claims] (1) The electron beam is sequentially irradiated onto the R, G, B, etc. phosphors that emit light when irradiated with the electron beam, and the amount of electron beam irradiation to the R, G, B, etc. phosphors is controlled by a color video signal. , in a method of driving an image display device that displays a color image, the ratio of the amount of light emitted by each phosphor such as R, G, B, etc.
A method for driving an image display device, characterized in that the ratio of electron beam irradiation time to irradiate each of phosphors such as , G, B, etc. is set based on the ratio of electron beam irradiation time. (2) A patent claim characterized in that the ratio of the electron beam irradiation time to each of the R, G, B, etc. phosphors is the ratio at which white light is synthesized by the light emission of the R, G, B, etc. phosphors. A method for driving an image display device according to scope (1). (3) The chromaticity of white color is adjusted by the ratio of electron beam irradiation time to each of the R, G, B, etc. phosphors, as described in claim (1) or (2). A method for driving an image display device.