JPH0152859B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a flat panel image display device. An object of the present invention is to align an electrode assembly composed of a linear electron source as a beam source, an electron beam extraction means, an electron beam control means, an electron beam deflection means, etc., and a light emitting means coated with a fluorescent substance or the like. By using a deflection electrode divided into multiple pairs as the deflection means and applying a different deflection voltage to each pair, the electron beam can be deflected more accurately and blurred images such as color shift can be avoided. It is to remove. Yet another object is to easily adjust the alignment by using an adjusting means.

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

This display element is arranged in order from the back to the front.
A rear electrode 1, a line cathode 2 as a beam source, vertical focusing electrodes 3, 3', a vertical deflection electrode 4, a beam flow control electrode 5, a horizontal focusing electrode 6, a horizontal deflection electrode 7, a beam accelerating electrode 8, and a screen plate 9 are arranged. These are housed in the evacuated interior of a flat glass bulb (not shown).

Here, a linear cathode 2 is used as a linear electron source, and vertical focusing electrodes 3 and 3' are used as electron beam extraction means.
a beam flow control electrode 5 as an electron beam control means;
Vertical and horizontal deflection electrodes 4 and 7 serve as electron beam deflection means, and screen plate 9 serves as light emitting means.

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, and a plurality of line cathodes 2 (here, 2-2-4
(Only books shown) provided. In this embodiment, it is assumed that 15 pieces are provided. 2i~2ta. These line cathodes 2 have a diameter of, for example, 10 to 20 μφ.
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. 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. The back electrode 1 may be formed by a coating of a conductive material applied to the inner surface of the rear wall of the glass bulb. Further, instead of the back electrode 1 and the linear cathode 2, a planar electron beam emitting cathode may be used.

The vertical focusing electrode 3 is a conductive plate 11 having a horizontally long slit 10 facing each of the line cathodes 2a to 2ta, and takes out the electron beam emitted from the line cathode 2 through the slit 10 and directs the electron beam vertically. focus in a direction. (The slit 10 may be provided with crosspieces at appropriate intervals in the middle, or may be substantially configured as a slit by a row of through holes arranged in a row at small intervals (almost touching) in the horizontal direction. ). The vertical focusing electrode 3' is also similar.

A plurality of vertical deflection electrodes 4 are arranged horizontally in the middle of each of the slits 10, and are each composed of conductors 13 and 13' provided on the upper and lower surfaces of an insulating substrate 12. has been done. And the opposing conductors 13, 13'
A vertical deflection voltage is applied between them to deflect the electron beam in the vertical direction. In this embodiment, the electron beam from one line cathode 2 is vertically deflected to positions corresponding to 16 lines by a pair of conductors 13, 13'. Then, the 16 vertical deflection electrodes 4 constitute 15 pairs of conductors corresponding to each of the 15 2's, and in the end, the electron beam is deflected to draw 240 horizontal lines on the screen 9. do.

Next, the control electrodes 5 each consist of a conductive plate 15 having a long slit 14 in the vertical direction, and a plurality of control electrodes 5 are arranged in parallel in the horizontal direction at predetermined intervals. In this embodiment, 320 control electrode conductive plates 15a to 15n are provided (only 10 are 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 the 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. Also,
In order to display images in color, each picture element is R,
Display is performed using phosphors of three colors, G and B, and the R, G, and B video signals are sequentially applied to each control electrode 5. In addition, 320 sets of video signals for one line are simultaneously applied to the 320 control electrodes 5.
Video for each line is displayed at once.

The horizontal focusing electrode 6 is composed of a conductive plate 17 having a plurality of 320 vertically long slits 16 facing the slits 14 of the control electrode 5, and focuses the electron beam for each pixel divided in the horizontal direction. Each focuses horizontally into a narrow beam of electrons.

The horizontal deflection electrode 7 is composed 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 picture element. The electron beams are respectively deflected in the horizontal direction, and the R, G, and B 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 accelerates the electron beam so that it collides with the screen 9 with sufficient energy.

The screen 9 is constructed by coating the back side of a glass plate 21 with a phosphor 20 that emits light when irradiated with an electron beam, and adding a metal back layer (not shown). The phosphor 20 has R,
One pair each of three color phosphors, G and B, are provided and are applied in stripes in the vertical direction. In FIG. 1, the broken lines drawn on the screen 9 indicate divisions in the vertical direction displayed corresponding to each of the plurality of line cathodes 2, and the two-dot chain lines indicate the divisions in the vertical direction corresponding to the plurality of line cathodes 2.
Shows the horizontal divisions displayed corresponding to each. As shown in the enlarged view in Figure 2, one section partitioned by these two has R, G, and B phosphors 20 for one pixel in the horizontal direction, and 16 lines in the vertical direction. It has a width of The size of one section is, for example, 1 mm in the horizontal direction and 16 mm in the vertical direction.

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

In addition, in this embodiment, only one pair of R, G, and B phosphors 20 for one picture element is provided for one control electrode 5, that is, one electron beam, but two
Of course, two or more pairs for more than one picture element may be provided, and in that case, R, G, and B video signals for two or more picture elements are sequentially applied to the control electrode 5.
At the same time, horizontal deflection is performed synchronously.

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 emit raster light will be described.

The power supply circuit 22 is a circuit for applying a predetermined bias circuit voltage (operating voltage) to _each electrode of the display element.
DC voltages of V ₃ and _V 3 ' are applied to the electrodes 3', V ₆ ' to the horizontal focusing electrode 6, V ₈ to the accelerating electrode 8, and V 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 pulse light emitting circuit 25 is composed of a counter that is reset by a vertical pulse and counts horizontal pulses, and is configured to operate during an effective vertical scanning period (in this case, 240 hours) excluding the vertical retrace period of the vertical period. 15 drive pulses, each having a length of 16H period, are generated sequentially during the following period. This drive pulse rotor is applied to the line cathode drive circuit 26, where it is inverted so that it is brought to a low potential only during each pulse period and approximately 20
The line cathode drive pulses made at a high potential of volts are converted into drive pulses i', ro'...ta', and each line cathode 2
A, 2ro...Added to 2ta. Each line cathode 2
...The two terminals are heated by a current flowing between the high potential of the drive pulse I' and the drive pulse I'.
The heated state is maintained so that electrons can be emitted even during the low potential period of -ta'. As a result, electrons are emitted from the 15 line cathodes 2i to 2ta only during the 16H period in which low potential drive pulses i' to ta' are applied to each of them. During the period when a high potential is applied, the potential at the line cathode 2 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 applied high potential is positive, the line cathode 2
No electrons are emitted from A to 2 T. Thus,
At the line cathode 2, during the effective vertical scanning period,
Electrons are sequentially emitted from the upper line cathode 2a to the lower line cathode 2a for 16H periods. The emitted electrons are pushed forward by the back electrode 1, pass through the opposing slits 10 of the vertical focusing electrode 3, and are focused in the vertical direction to form a flat electron beam.

Next, the vertical deflection drive circuit 27 is composed of a counter that is reset by each of the vertical drive pulse generators and counts horizontal synchronizing signals, a conversion circuit that converts the count output from D/A, and the like. , generates a pair of vertical deflection signals V, V' which change in 16 steps by 1H during the 16H period of each vertical drive pulse generator. The vertical deflection signals V and V′ both have a center voltage of V ₄ and increase sequentially by V,
V′ is configured to change in opposite directions so as to decrease sequentially. These vertical deflection signals V and V' are applied to the electrode 13 of the vertical deflection electrode 4, respectively.
and 13', and as a result, the electron beams generated from each of the line cathodes 2a to 2ta are vertically deflected in 16 steps. The raster is deflected to draw 16 lines of raster one line at a time from the top.

As a result of the above, electron beams are emitted from the top of the 15 line cathodes 2A to 2T for a period of 16 hours, 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 one by one, 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 lines of raster are drawn.

The electron beam thus vertically deflected is horizontally deflected by 320 degrees by the control electrode 5 and the horizontal focusing electrode 6.
It is divided into sections and taken out. Figure 1 shows one of these categories. The amount of electron beam passing through each section is controlled by a control electrode 5, and horizontally focused by a horizontal focusing electrode 6 into a single narrow electron beam. The R, G, and B phosphors 20 on the screen 9 are deflected in three steps in the horizontal direction.
are irradiated sequentially.

That is, the horizontal drive pulse generation circuit 28 is composed of three cascaded monostable multivibrators, etc., and is triggered by a horizontal synchronization signal to generate three horizontal drive pulses with equal pulse widths in one horizontal period. Generate r, g, b. here,
As an example, three pulses r, g, and b are generated during an active horizontal scanning period of 50 μsec, with each pulse width being approximately 17 μsec.
These horizontal drive pulses r, g, and b are applied to the horizontal deflection drive circuit 29. This horizontal drive circuit 29
A pair of horizontal deflection signals h that are switched in three stages by horizontal drive pulses r, g, and b;
generate h′. The horizontal deflection signals h and h' both have a center voltage of _V7 , and change in opposite directions such that h increases sequentially and h' decreases sequentially.
These horizontal deflection signals h, h' are applied to electrodes 18 and 18' of the horizontal deflection electrode 7, respectively. As a result, each horizontally divided electron beam is horizontally deflected so as to sequentially irradiate the R, G, and B phosphors of the screen 9 for 17 μsec during each horizontal period. 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, if the odd-numbered electron beams are deflected in the order of R→G→B, the even-numbered electron beams are deflected in the order of R→G→B. Conversely, it is deflected in the opposite direction every other section, such as in the order of B→G→R.

Thus, in each line raster, the electron beam is divided into R, G,
Each of the B phosphors 20 is sequentially irradiated with light.

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

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

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

On the other hand, the sampling reference clock oscillator 33
is composed of a PLL (phase locked loop) circuit, etc., and generates a reference clock of about 6.4 MHz in this embodiment. The reference clock is controlled to always have a constant phase with respect to the horizontal synchronizing signal H. This reference clock is applied to the sampling pulse generation circuit 34, where it is delayed by one clock cycle by a shift register, etc., so that the reference clock is applied to the sampling pulse generating circuit 34, where it is delayed by one clock cycle at a time, so that the reference clock is Sampling pulses a to n are sequentially generated, and then one transfer pulse is generated. These sampling pulses a to n correspond to each picture element when one line of the video to be displayed is divided horizontally into 320 picture elements, and their positions are always constant with respect to the horizontal synchronizing signal H. controlled.

These 320 sampling pulses a to n correspond to the above 320 sample and hold circuit sets 31.
a to 31n, thereby providing one line to each sample and hold circuit set 31a to 31n.
R of each picture element when divided into 320 picture elements,
Each G and B video signal is sampled individually,
will be held. That sample was held
320 sets of R, G, and B video signals are stored in 320 sets of memories 32a to 3 after completing the sample hold for one line.
2c, they are transferred all at once by a transfer pulse t, and are held here for the next one horizontal period.

One line of R, G, and B video signals held in the memories 32a to 32n are applied to 320 switching circuits 35a to 35n, respectively. The switching circuits 35a to 35n each have R, G,
B individual input terminals and a common power terminal that sequentially switches and outputs them, and the output of each switching circuit 35a to 35n is used as a control signal for modulating the electron beam to the control electrode 5 of the display element.
It is individually applied to each of the 320 conductive plates 15a to 15n. Each switching circuit 35a to 35n
is applied from the switching pulse generation circuit 36. Switching is simultaneously controlled by switching pulses. The switching pulse generation circuit 36 receives the pulses r,
The switching circuits 35a to 35n are controlled by dividing approximately 50 μsec at the center of each horizontal period into three and switching circuits 35a to 35n for approximately 17 μsec each to switch R, G,
Each video signal of B is time-divided and outputted alternately and sequentially,
Switching signals r, g, and b are generated to supply control electrodes 15a to 15n. However, among the switching circuits 35a to 35n, the odd-numbered switching circuits 35a, 35c, . . . are switched in the order of R→G→B, and the even-numbered switching circuits 35
b, 35d...35n are configured to be switched in the reverse order of B→G→R.

What should be noted here is that the switching circuit 3
The switching of the supply of R, G, and B video signals in 5a to 35n and the horizontal deflection of the electron beam irradiation to the R, G, and B phosphors by the horizontal deflection drive circuit 29 are performed perfectly in both timing and order. It is 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 B of each picture element are controlled in the same manner. The light emission of each B phosphor is controlled by the R, G, and B video signals of that picture element, and 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 line of video, and then sequentially performed for 240 lines starting from the upper line, so that one video is displayed on screen 9. will be done.

The above operations are repeated for each field of the input television signal, and as a result,
The screen 9 is similar to a normal television receiver.
The television footage of the video is shown above.

The following problems arose in the flat panel image display device as described above. This drawback will be explained below.

The horizontal deflection electrode 7 is made of 42-6 alloy (42% Ni,
Manufactured by etching a plate (6% Cr, balance Fe). The same applies to other control electrodes. Also R, G, B
The method for applying the phosphor 20 is to form a pattern using a glass mask, and then expose the uniformly applied phosphor film to light.
Perform development, washing, drying, etc. At this time, it is difficult to precisely align the phosphor 20 with the electrode structure including the horizontal deflection electrode 7 and other electrodes. This is a method for manufacturing an electrode structure such as the horizontal deflection electrode 7, and R, G,
B. This is because the manufacturing method of the phosphor 20 is different. The electrode assembly is exposed to light with a glass mask in complete contact with it, but the phosphor film is exposed with a distance of about 0.5 to 1 mm from the mask. Also, the temperature difference during exposure is 1
If the temperature is different, a 42-6 alloy plate with a length of about 30 to 40 cm will have a difference of several μm to several tens of μm.

For these reasons, the pitches of the R, G, and B phosphors 20 and the electrode structure, especially the horizontal deflection electrode 7 facing the phosphor film, are not necessarily the same, and the R, G, and B phosphors 20 do not always have the same pitch.
When the G, B, phosphor 20 and the horizontal deflection electrode 7 are aligned at the center, an accumulated error of about ±10 to 100 μm occurs at both ends. For this purpose, when the same deflection voltage is applied to each pair of horizontal deflection electrodes, the positions where the electron beam impinges slightly toward both ends are sequentially arranged in the same direction as the direction of deflection by the horizontal deflection electrodes 7. The positions of the R, G, and B phosphor films will shift. For example, near the center, the red color of R is displayed, but toward both ends, the red color becomes greenish or bluish, resulting in color shift.

The present invention attempts to eliminate the above-mentioned conventional drawbacks by using a deflection electrode divided into a plurality of pairs as an electron beam deflection means and applying a different deflection voltage to each pair. . Furthermore, by applying the deflection voltages at the same time through mutually interlocking adjustment means, the drawbacks of the prior art are more easily overcome.

An embodiment of the present invention will be explained based on FIGS. 4 and 5. FIG. 4 is a partially enlarged view of the horizontal deflection electrode 7 shown in FIG. 1 and electrically connected thereto. Fifth
The figure shows the horizontal deflection electrodes (divided into 3 pairs in the figure)
A wiring diagram between each pair and an applied signal pulse waveform diagram are shown. First, the deflection means is _electrically divided into three pairs of deflection electrodes as shown in FIG _. 4, and as shown in _FIG .
Resistors R ₁ , R ₂ , and R ₃ are connected in series, and a variable voltage is applied to both ends. When deflection pulse signals are applied to the signal application points 51 and 52 in such a state, the signal voltages applied to the B ₁ , B ₂ , and B ₃ electrodes by the variable power source 53 are
3, the voltages divided by the resistors R ₁ , R ₂ , and R ₃ are added, and A ₁ , B ₁ ; A ₂ , B ₂ ; A ₃ B ₃ ;
The voltages applied to the pair of deflection electrodes made up of the electron beams differ slightly in steps, and the deflection distances of the electron beams deviate from each other. This slight deviation corrects the pitch deviation with the phosphor, making it more accurate.
Misalignment between the electrode structure and the phosphor can be corrected, and a clearer image can be provided.
The variable power supply and the resistors R ₁ , R ₂ , and R ₃ constitute adjustment means that operate in conjunction with each other. Of course, the same effect can be obtained by applying a deflection pulse signal to each electrode pair separately.

A more detailed embodiment of the present invention will be described with reference to FIG. The horizontal deflection electrodes in the basic configuration example shown in FIG. 1 form a pair of deflection electrodes for one electron beam at a pitch of 1 mm, and the electron beam passage slit width of the pair is about 300 μm. For example, if this becomes the size of a 16-inch television screen,
Since the size is 320 mm x 240 mm, the horizontal deflection electrode is composed of 320 pairs of electrodes. Further, it is assumed that the deviation from the R, G, and B phosphor films is about 100 to 150 μm at both ends. (This is not necessarily constant depending on the mask pattern, manufacturing of the electrode structure, etc.) At this time, the horizontal deflection electrodes are electrically formed into three pairs, and one end of the pair is always exposed to an electron beam of about 100 μm. A deflection pulse signal that adds the displacement of the deflection distance is applied, and to the other pair of ends, a deflection pulse signal that adds the displacement of the same magnitude as the above is applied in the opposite direction. Specifically, as shown in FIG. 5, the voltage is divided by resistors R ₁ , R ₂ , and R ₃ connected to a variable power source, and one electrode of the pair of electrodes A ₁ B ₁ at one end is divided. B ₁
The signal waveform 54 applied to the signal application point 52 is shown in FIG.
Unlike the signal waveform 54, a waveform 55 which is added by V ₁ voltage is applied.

Further, a waveform 56 obtained by subtracting the voltage V ₁ is applied to the electrode B ₃ at the other end, contrary to the waveform 55 . at this time
The V ₁ voltage varies depending on the electrode configuration, but is generally on the order of several volts to several hundred volts. Furthermore, the signal waveform 7 applied to the signal application point 51 is commonly applied to the A ₁ , A ₂ , and A ₃ electrodes, which are one of the paired electrodes. As a result, the electron beam in the deflection electrode made up of the A ₁ and B ₁ electrodes is always subjected to a large displacement of about 100 μm compared to the deflection electrode made up of A ₂ B ₂ . Of course, the A ₃ B ₃ electrodes will similarly give displacement in the opposite direction.

In this way, the positional shift with respect to the phosphor can be adjusted with higher precision. At the very least, there is no possibility of color shift and a clearer image can be obtained.

In addition, by configuring a variable power supply, resistors R ₁ , R ₂ , R _3, etc. as adjustment means that are linked to each other, it is possible to easily adjust only the variable power supply without having to adjust color shift separately. This has the effect of eliminating color shift.

As explained above, the method for driving a flat panel image display device of the present invention is capable of obtaining clear images without color shift, and has high industrial utility value.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram of a flat panel image display device, Fig. 2 is an enlarged view of the main part of the phosphor film on the screen in the same device, and Fig. 3 is a basic driving method of the device. 4 is a configuration diagram of a deflection electrode for explaining the driving method of a flat panel image display device of the present invention, and FIG. 5 is a configuration diagram of a deflection electrode for explaining an embodiment of the same driving method. be. 2... Line cathode (linear electron source), 3, 3'... Vertical focusing electrode (electron beam extraction means), 4... Electron beam deflection means (vertical deflection means), 5... Beam flow control electrode (electron beam extraction means)... beam control means), 7... electron beam deflection means (horizontal deflection electrode), 9... light emitting means (screen plate).

Claims (1)

[Claims] 1. To control linear electron sources arranged in a plurality of rows and electron beams from the linear electron sources arranged in a direction intersecting the linear electron sources based on an input video signal. an electron beam control means for deflecting the electron beam in a predetermined direction; and an electron beam deflection means for deflecting the electron beam in a predetermined direction; In a flat panel image display device comprising a light emitting means in which a B phosphor is arranged, the electron beam deflection means is constituted by a deflection electrode electrically divided into a plurality of pairs, each pair having a deflection electrode and an R ,
1. A method for driving a flat panel image display device, characterized in that different deflection voltages are applied to compensate for pitch deviations in the arrangement of G and B phosphors. 2. A flat plate image according to claim 1, characterized in that the deflection voltages applied to each pair of the deflection electrodes divided into a plurality of pairs are simultaneously applied via adjusting means that respectively interlock with each other. A method for driving a display device.