JPH0139627B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a flat panel image display device.

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 back 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. They are housed within the evacuated interior of a flat glass bulb (not shown).

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) are provided. In this embodiment, it is assumed that 15 pieces are provided. 2i~2ta. These line cathodes 2 have a diameter of 10 to 20μφ, for example.
An oxide cathode material is coated on the surface of a tungsten wire. Then, as will be described later, the electron beams are controlled to be emitted sequentially from the upper line cathode 2a for a fixed period of time. (The back electrode 1 suppresses 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 directs the generated electron beams only in the forward direction. )
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 a row of many through holes arranged horizontally at small intervals (almost touching), and can be used as a slit. ) 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'. And, by 16 vertical deflection electrodes 4, 15
Fifteen conductor pairs corresponding to each of the book line cathodes 2 are constructed, and the electron beam is ultimately deflected to draw 240 horizontal lines on the screen 9.

Next, the control electrodes 5 are composed of conductive plates 15 each having a vertically long slit 14, and a plurality of control electrodes 15 are arranged in parallel in the horizontal direction at predetermined intervals. In this embodiment, 320 conductive plates 15a to 15n for control electrodes 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 is focused horizontally into a narrow electron beam.

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 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 back layer (not shown). The phosphor 20 is arranged for each slit 14 of the control electrode 5, that is, for each horizontally divided electron beam.
Pairs of phosphors of three colors, R, 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 that are displayed corresponding to each of the plurality of line cathodes 2, and the two-dot chain lines correspond to each of the plurality of control electrodes 5. Indicates the horizontal division displayed. As shown in the enlarged view in Figure 2, one section partitioned by these two has R, G, and B phosphors 20 for one picture element in the horizontal direction, and 16 lines in the vertical direction. It has a width.
For example, the size of one section is 1 in the horizontal direction.
mm, and the vertical direction is 16 mm.

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

Further, in this embodiment, only one pair of R, G, and B phosphors 20 for one picture element is provided for one control electrode 5, that is, one electron beam, but two
Of course, two or more pairs for more than two picture elements 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.
Horizontal deflection is performed in synchronization with this.

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 voltage (operating voltage) to each electrode of the display element,
-V ₁ to the back electrode 1, and -V 1 to the vertical focusing electrodes 3 and 3'.
DC voltages of V ₃ , V ₃ ', V ₆ to the horizontal focusing electrode 6, V ₈ to the accelerating electrode 8, and V 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. The vertical drive pulse generation 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 (here, 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
A line cathode drive pulse I′ made at a high potential of volts,
It is converted into B′...T′, and each line cathode 2a, 2b,...
...Added to 2 ta. Each line cathode 2a, ... 2ta is heated by a current flowing through it during the high potential of the drive pulses I' to T', and can emit electrons even during the low potential period of the drive pulses I' to T'. The heated state is maintained. As a result, 15 wire cathodes 2-2
Each low-potential drive pulse
Electrons are emitted only during the 16H period when the data is added. (During the period when a high potential is applied, the potential at the line cathode 2A to 2T 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 high potential applied to the line cathode 2 is positive,
No electrons are emitted from 2 ta. Thus, in the line cathode 2, during the effective vertical scanning period, from the upper line cathode 2a to the lower line cathode 2a,
Electrons are emitted every 16H period. 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 V increases sequentially,
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, which is then controlled by horizontal deflection means described below. The R, G, and B phosphors 2 on the screen 9 are deflected horizontally in three stages.
0 is sequentially irradiated.

That is, the horizontal drive pulse generation circuit 28 is composed of three cascade-connected monostable multivibrators, etc., and is triggered by a horizontal synchronization signal to generate three horizontal drives with equal pulse widths within one horizontal period. Generate pulses r, g, b. Here, as an example, each pulse width is approximately 17 μsec.
As, 3 during the active horizontal scanning period of 50μsec.
Three pulses r, g, and b are generated. These horizontal drive pulses r, g, and b are applied to the horizontal deflection drive circuit 29. The horizontal deflection drive circuit 29 generates a pair of horizontal deflection signals h and h' that change in three stages by being switched by the horizontal drive pulses r, g, and b. Both horizontal deflection signals h and h' have a center voltage of V ₇ , and h increases sequentially,
h' change in opposite directions so that they decrease 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, one conductor 18 or 18' is used in the horizontal deflection electrode 7.
is used to deflect the electron beams of two adjacent sections, and is designed to produce a deflection effect on the adjacent electron beams in mutually opposite directions. Therefore, the electron beam of 320 sections is If the thing in the th category is deflected in the order of R→G→B, the thing in the even numbered category is deflected in the order of B→G→R.
It is deflected in the opposite direction every other section, such that it is deflected in the order of .

Thus, in each line raster, the electron beams are divided into R, G, and B in each of the 320 horizontal sections.
The light is sequentially irradiated onto each of the phosphors 20 .

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 input terminal 23 is applied to the color demodulation circuit 30,
Here, the color difference signals of R-Y and B-Y 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,
B primary color signals (hereinafter referred to as R, G, and B video signals) are output. These R, G, and B video signals are processed by 320 sample and hold circuit sets 31a to 3.
Added to 1n. Each sample hold circuit group 3
1a to 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 held by memory sets 32a to 32n, respectively.
32n.

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 into 320 picture elements in the horizontal direction, and their positions are always constant with respect to the horizontal synchronizing signal H. controlled by.

These 320 sets of sampling pulses a to n correspond to the above 320 sets of sample and hold circuit set 31.
a to 31n, thereby providing one line to each sample and hold circuit set 31a to 31n.
When divided into 320 picture elements, the R, G, and B video signals of each picture element are individually sampled and held. The sampled and held 320 sets of R, G, and B video signals are stored in 320 sets of memories 32a to 32a after completion of sample and hold for one line.
32c by a transfer pulse t,
Here, it is held 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 output terminal that sequentially switches and outputs them, and the output of each switching circuit 35a to 35n is sent to the control electrode 5 of the display element as a control signal for modulating the electron beam.
are individually applied to each of the 320 conductive plates 15a to 15n. Each switching circuit 35a to 35
n are simultaneously switched and controlled by a switching pulse applied from a switching pulse generating circuit 36. The switching pulse generation circuit 36 receives pulses r,
R, G, B are controlled by R, G,
Each video signal of B is time-divided and outputted alternately and sequentially,
Switching signals r, g, and b are generated to be supplied to 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 35a, 35c...
5b, 35d...35n are configured to be switched in the reverse order of B→G→R.

What should be noted here is the switching of the supply of R, G, and B video signals in the switching circuits 35a to 35n, and the horizontal switching of the irradiation of the electron beam to the R, G, and B phosphors by the horizontal deflection drive circuit 29. The deflection is controlled synchronously so that both the timing and the order of the deflections are exactly the same. As a result, when the electron beam is irradiating the R phosphor, the irradiation amount of the electron beam is R
The G and B phosphors are controlled in the same way by the video signal, and the light emission of the R, G, and B phosphors of each picture element is controlled by the R, G, and B video signals of that picture element. 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 furthermore,
This is performed sequentially for 240 lines starting from the upper line, and one image is displayed on the screen 9.

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 flat panel image display device described in detail above is
Unlike ordinary television receivers in which the electron gun is housed in a large cathode ray tube, the depth can be made extremely small and the plate can be made flat, and the weight can also be reduced.

However, there are problems that are hindering efforts to make the device even flatter and lighter. In order to prevent the vacuum container (glass plate) 21 that houses the various electrodes shown in Figure 1 from being destroyed by atmospheric pressure, the thickness of the plate must be increased. This is where it gets heavy.

Therefore, in order to reduce the weight of the vacuum container 21, if the shape of the vacuum container 21 is made into a curved surface with curvature, the vacuum withstand pressure can be sufficiently maintained and the glass plate thickness can be reduced, resulting in weight reduction. However, when this is done, the display surface, which was conventionally flat, now has a curved surface, and when the above-mentioned electrode configuration is used as it is in a glass container with a curved display surface, FIGS.
As shown in Figure 2, a problem occurred in which the image quality became uneven.

4b and 4c show the appearance of the display surface when the display glass 21 shown in FIG. 4a is made into a curved surface in order to increase the withstand pressure of the vacuum container in the electrode configuration of FIG. 1 already explained. There is. Note that FIG. 4b is an enlarged view of local portions A at the left and right ends of the display glass 21, and FIG. 4c is an enlarged view of the central portion B of the display glass 21.

As can be seen from FIG. 4b, at the end A of the display surface, the electron beams 42 are directed to the red (R), green (G), and blue (B) phosphors sandwiched between the light-shielding blacks 41. The electron beam 4 hits the red (R) and blue (B) phosphors accurately, but at the center B of the display screen, as shown in Figure 4c, the electron beam 4 that should hit the red (R) and blue (B) phosphors
3 is off from the phosphor part. If the electron beam deviates from a predetermined phosphor and hits the display screen in this way, image deterioration such as color shift occurs.

As described above, when the display surface is curved in order to reduce the weight of the vacuum container and increase its pressure resistance, there is a drawback that the image deteriorates. This is because when the display surface is curved, the travel distance for the electron beam to pass through the deflection electrode and reach the display surface is different at each part of the display surface.
If a constant deflection voltage is applied to any part of the horizontal deflection electrode as in the past, the deflection distance will be different in each part of the linear electron beam, which may cause the electron beam to no longer hit the border of the display area or This is because a phenomenon in which the beams overlap and collide occurs, resulting in image deterioration.

The present invention solves the above problem by varying the distance between each pair of conductors constituting the horizontal deflection electrode in correspondence with the curvature of the display surface, thereby varying the electron beam deflection distance at each part of the display surface. This is what I am trying to do.

The principle of the present invention will be explained above.

In the flat panel image display device of the present invention, the electron beam deflection is electrostatic deflection. In addition, in FIG. 5, only the portions corresponding to the horizontal deflection electrodes 7, 18, 18' and the screen plate 9 in FIG. 1 are extracted and drawn to simplify the explanation. Note that FIG. 5 is a view of the horizontal deflection electrode 7 viewed from direction D in FIG. In general, the deflection distance h in electrostatic deflection is approximately determined by the following equation, as shown in FIG.

h≒Ltanθ=VdL/2aV ₀ ...(1) Here, as shown in the same figure, L is the center point of the electron beam horizontal deflection electrodes 18, 18' and the screen plate 9.
_The distance to This is an accelerating voltage applied between the deflection electrodes 18 and 18'.

As can be seen from the above equation (1), the horizontal deflection electrodes 18, 1
It can be seen that as the distance L between the center point of the screen 8' and the screen plate 9 increases, the deflection distance h of the electron beam on the screen plate 9 increases accordingly.
As shown earlier, when the screen plate 9 is made into a curved surface, the image deteriorates because the distance L differs at each location on the screen plate 9, and the electron beam deflection distance varies over the entire surface of the screen plate 9. This is because the light does not strike each phosphor accurately.

On the other hand, as can be seen from the above equation (1), the horizontal deflection electrode 1
As the distance a between the horizontal deflection electrodes 18 and 18' increases, the deflection distance h on the screen plate 9 decreases, and conversely, as the distance a between the horizontal deflection electrodes 18 and 18' decreases, the deflection distance on the screen plate 9 decreases. It can be seen that the distance h increases.

As a result, even if the screen plate 9 becomes a curved surface and the distance L between the horizontal deflection electrodes 18, 18' and the screen plate 9 changes in size at each location on the screen plate 9, the horizontal deflection electrode 18 and 1
By varying the distance a between 8', the deflection distance h of the electron beam can be kept constant over the entire surface of the screen plate 9.

Embodiments of the present invention will be described based on the drawings.
FIG. 6 shows a flat panel image display device according to an embodiment of the present invention, in which a screen plate 59 has a curved surface that projects slightly outward so as to withstand atmospheric pressure. Here, the screen plate 59 has a diagonal length of 16 inches and a curved surface.
It is part of a cylindrical body with a radius of about 500 to 800 mm. By forming the screen plate 59 into such a shape, the withstand pressure of the vacuum container can be sufficiently increased even if the screen plate 59 is made thin.

The feature of this device is that while the screen plate 59 is curved, the mutual spacing of the horizontal deflection electrodes 7 ₁ , 7 ₂ . . . 7 ₁₁ is changed.

That is, as shown in FIG. 6, horizontal deflection electrodes 7 ₁ and 7 ₂ , 7 ₂ and 7 ₃ , and 7 ₃ and 7 are arranged in a row horizontally.
₄ , 7 ₄ and 7 ₅ , 7 ₅ and 7 ₆ , 7 ₆ and 7 ₇ , 7 ₇ and 7 ₈ , 7 ₈
and the respective intervals between 7 ₉ , 7 ₉ and 7 ₁₀ , and 7 ₁₀ and 7 ₁₁ as d ₁ , d ₂ , d ₃ , d ₄ , d ₅ , d ₅ , d ₄ , d ₃ , d ₂ , d ₁ , Then, there is a magnitude relationship of d ₁ < d ₂ < d ₃ < d ₄ < d ₅ .

In other words, even if the distance L between the center point of the horizontal deflection electrodes 7 ₁ ... 7 ₁₁ and the screen plate changes by bending the screen plate 59, the horizontal deflection electrodes will change according to L. 7 ₁
By varying the distances d ₁ ... d ₅ between ...7 ₁₁ , it is possible to always maintain the same deflection distance over the entire surface of the screen plate 59.

In this device, the distance between each pair of conductors constituting the electron beam horizontal deflection electrode is made different depending on the curvature of the display surface, which has the effect of eliminating color shift and obtaining higher quality images. be.

The dimensions, materials, etc. of the horizontal deflection electrode shown in FIG. 6 will be specifically explained. The horizontal deflection electrodes 7 ₁ , 7 ₂ ... 7 ₁₁ are
42-6 alloy plate (42% Ni6% Cr, 52
%Fe) by forming a pair of two stripe-shaped conductors and etching them so that they are arranged at a pitch of 1 mm. Size is 340mm x 260
It is about mm.

The state of horizontal deflection at the center and both ends of the screen plate 59 in this case is illustrated by solid lines A and B with arrows in FIG. 7, respectively. Central part B
The distance between the horizontal deflection electrodes 7 ₅ and 7 ₆ is approximately 0.3 mm,
When the distance between the pair of horizontal deflection electrodes 7 ₁ and 7 ₂ of the deflection electrodes at one of the ends A is about 0.2 mm, when the same deflection voltage is applied to the horizontal deflection electrodes 7 ₁ ... 7 ₁₁ (50V ~100V (p-p)), screen plate 5
The screen voltage at this time is about 5V to 10KV to obtain almost the same deflection distance on the entire surface of the screen.

As described above, in the flat panel image display device of the present invention, the distance between each electron beam horizontal deflection electrode is made different depending on the curvature of the display surface, thereby making the deflection distance of the electron beam the same and preventing color shift. This has the effect of allowing you to obtain a better quality image than if you were to remove it.

As explained above, in response to the curved display surface of the flat panel image display device of the present invention, the structure of the electrodes related to the deflection of electron beams has been modified, and the image quality has been improved. It is extremely useful.

[Brief explanation of drawings]

Figure 1 is a basic configuration diagram of the electrodes of a flat panel image display device, Figure 2 is an enlarged view of the main parts of the screen plate of the same device, and Figure 3 is a basic configuration diagram of the drive circuit of the device. 4a, b, and c are diagrams showing nonuniform images seen in conventional examples, FIG. 5 is a diagram for explaining the principle of electrostatic deflection in a flat panel image display device, and FIG. 6 is an embodiment of the present invention. FIG. 7 is a diagram showing the configuration of the flat panel image display device in FIG. 1... Back electrode, 2... Line cathode, 3, 3'...
Vertical focusing electrode, 64...Vertical deflection electrode, 63,6
3'... Conductor, 5... Beam flow control electrode, 6...
...Horizontal focusing electrode, 7 ₁ , 7 ₂ ...7 ₁₁ ... Horizontal deflection electrode, 8 ... Beam acceleration electrode, 59 ... Screen plate.

Claims (1)

[Claims] 1. An electron beam horizontal deflection electrode consisting of a plurality of linear cathodes, a plurality of electron beam control electrodes, an electron beam vertical deflection electrode, and a plurality of pairs of conductors arranged in a line in a predetermined direction. and a light-emitting means formed into an outwardly projecting curved surface that emits light upon impact of an electron beam, the plurality of pairs of conductors having a longer distance from the light-emitting means to the center conductor pair. 1. A flat panel image display device, characterized in that the distance between the conductors is set so that the deflection distance of the electron beam is the same over the entire surface of the flat panel image display device.