JPS5828703B2 - picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flat picture tube, and particularly aims to improve the luminance of light emission and simplify the driving circuit by combining a matrix method and an electron beam scanning method.

For example, phosphors for low-speed electron beams have low luminance and are limited to direct current applications such as fluorescent display tubes.

Recently, the luminous efficiency of this low-speed electron beam phosphor has improved, for example, the luminance has increased from 5,000 fj-L to 10,000 fj-L.
000fj-L phosphor is also being produced.

However, even with this phosphor, when using a dot sequential scanning method such as a normal cathode ray tube, if the number of pixels in the horizontal direction is 400, it becomes 4.5 x 10"ft L, which is not practical. It cannot be offered to

On the other hand, an X-Y matrix display has been proposed as an alternative to cathode ray tubes, but in this case a drive circuit is required for each of the X and Y electrodes, making the circuit configuration complicated. do not have.

In view of the above-mentioned points, the present invention provides a flat picture tube that can obtain sufficient luminance even when using a phosphor for low-speed electron beams, and can also simplify the driving circuit. It is something to do.

In the present invention, a plurality of strip-shaped control electrodes extending in one direction (column (vertical) direction or row (horizontal) direction) K are arranged in parallel with respect to the fluorescent surface constituting the screen. In addition, the video signals to be supplied to the row lines (so-called horizontal lines) or column lines (so-called vertical lines) of the screen are accumulated for each line, and this video signal is applied to the plurality of control electrodes simultaneously and line by line. A long strip-shaped electron beam is supplied at a constant speed along the direction in which the control electrode extends, and in synchronization with this, a long band-shaped electron beam is scanned at a constant speed along the direction in which the control electrode extends. The parts are excited and emitted line-sequentially to obtain a desired image.

According to such a picture tube, since the fluorescent surface is emitted line-sequentially by the band-shaped electron beam, the luminance of the screen is improved, and even if a phosphor for low-speed electron beams is used, for example, it is sufficiently practical. The emission brightness that can be used can be obtained.

In addition, one drive circuit is only for the control electrodes arranged in one direction, and the other direction is omitted by a band-shaped electron beam, so the structure of the one drive circuit can be greatly simplified. It is.

Hereinafter, embodiments of the picture tube according to the present invention will be described in detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention.

In this example, a flat tube body 1 made of glass or the like is provided, and on one inner surface 1a of this tube body 1, a plurality of (for example, 512) strip-shaped control electrodes 2C2 corresponding to the number of picture elements in the horizontal direction, ,2□,23,・・・・・・・・・・・・
] are arranged parallel to each other at a predetermined interval.

A phosphor layer 3 for low-speed electron beams is applied onto each control electrode 2 to form a phosphor surface 4 constituting a screen.

A mesh-like electrode 1 is arranged on the fluorescent surface 4 and facing the fluorescent surface 4 at a predetermined distance.

Further, on the other inner surface 1b of the tube body 1 facing the fluorescent surface 4, a band-shaped electron beam 5, which will be described later, is deflected toward the fluorescent surface 4 and scanned in the vertical direction (direction of arrow B in FIG. 2). A main deflection electrode 6 is provided.

This main deflection electrode 6 is formed of a transparent conductive layer.

On the other hand, a beam source 8 that emits a band-shaped low-velocity electron beam 5 is arranged beside the fluorescent surface 4, that is, at a lateral position with respect to the longitudinal direction of the control electrode 2.

The belt-shaped electron beam 5 from the beam source 8 is formed into a long belt-shaped beam in the horizontal direction so as to cover the metal peaks of the control electrodes 2 arranged in plurality.

The beam source 8 includes a tungsten cathode 9 stretched horizontally, an electrode 11 that surrounds the cathode 9 and has a slit 10 partially extending in the horizontal direction, to which a voltage approximately equal to that of the cathode 9 is applied, and a positive electrode 11. and an accelerating electric machine 13 to which a constant voltage is applied.

In this case, the accelerating electrode 13 is provided with a very narrow slit 12 for forming the object point of the beam 5.

Therefore, electrons from the cathode 9 are transferred to the slit 10 of the electrode 11.
and is extracted as a band-shaped electron beam 5 through the slit 12 of the accelerating electrode 13.

Further, in front of the beam source 8, a preliminary deflection electrode 14 consisting of a pair of electrode plates 14A and 14B, which deflects the band-shaped electron beam 5 in cooperation with the main deflection electrode 6, is arranged.

Since the preliminary deflection electrode 14 forms a so-called semicylindrical electron lens, the band-shaped electron beam 5 is well focused in the vertical direction of the screen.

In this configuration, an unmodulated band-shaped electron beam 5 is emitted from the beam source 8 parallel to the phosphor surface 4 and is deflected by the preliminary deflection electrode 14 and the main deflection electrode 6 before being incident on the fluorescer surface 4. along with the fluorescent surface 4 in the vertical direction (arrow B
direction) at a constant speed.

That is, in this case, by applying a deflection voltage such that the voltage on the main deflection electrode 6 side is low between the main deflection electrode 6 and the mesh-like electrode 7, the predeflected electron beam 5 that has passed through the preliminary deflection electrode 14 becomes fluorescent. The light is incident on the surface 4 side.

At this time, the main deflection voltage between the electrodes 6 and 7 is kept constant, and the preliminary deflection voltage between the electrode plates 14A and 14B is changed g-
By changing the main deflection voltage while keeping the pre-deflection voltage constant, or by changing both the pre-deflection voltage and the main deflection voltage, the band-shaped electron beam 5 is directed in the direction perpendicular to the screen (in the direction of arrow B). is scanned.

Note that this band-shaped electron beam 5 is scanned in the vertical direction in synchronization with one horizontal period of a video signal, which will be described later.

10,000, each video signal is accumulated every 1,000 cycles, and this 1
A video signal corresponding to a horizontal period is supplied to each control electrode 2 simultaneously and sequentially every horizontal period.

In this case, the video signal is transmitted to the horizontal picture element, that is, the control electrode 2
, and each sampling signal is supplied to each corresponding control electrode 2.

Therefore, when a video signal of 1,000 cycles is sequentially applied to the control electrodes 2, the phosphor layer 3 on each control electrode 2 is irradiated with the band-shaped electron beam 5, and the scanning of the band-shaped electron beam 5 sequentially The fluorescent surface 4 is excited and emitted in a line-sequential manner to obtain a desired image.

If there is no signal on the control electrode 2, the corresponding electron beam will be captured by the mesh electrode and will not reach the phosphor layer 3.

The emitted image is captured from the incident side of the piece 5, that is, from the direction of arrow A in FIG.

In order to obtain the brightness according to the signal, a modulation method in which the voltage applied to the control electrode 2 is varied, or a so-called pulse width modulation method in which the voltage is kept constant and the application time is varied, etc. can be used.

However, in the case of a modulation method that changes the voltage, pixels adjacent to a bright pixel (control electrode) become darker due to the low-speed electron beam because the electron beam is drawn toward the bright pixel. There is a possibility that it will happen a long time ago.

Therefore, in this example, it is preferable to use the pulse width modulation method for signal input.

FIG. 3 shows an example of a drive circuit employing a pulse width modulation method applied to drive the picture tube described above.

In the same figure, 21 is a sampling hold circuit, 22
23 is an 8-bit analog/digital converter circuit, and 23 is a multiple stage of parallel 8-bits (in this example, 5 stages corresponding to the number of control electrodes).
12 stages) shift register 24 [247, 242, 24
3,...], and stores one horizontal cycle of the video signal, and has an input terminal t.
The video signal for each horizontal period from 1 is processed by the sampling hold circuit 21 into a sampling signal corresponding to the picture elements of one horizontal line (512 picture elements), and each sampling signal is converted into a sampling signal through the analog-to-digital conversion circuit 22. 1
is stored in the shift register 24 of each corresponding stage of the shift register circuit 23.

Each of these accumulated signals is once connected to the same parallel 8-bit 51
Two-stage shift register 25 [25□, 252, 253,
] during the horizontal blanking period.

Further, the signals of the shift registers 25 at each stage to be applied to the second shift register circuit 26 are supplied to corresponding signal conversion circuits 27C27, 27□, 273, . . . ].

This signal conversion circuit 2T converts the signal from the shift register 25 into a required pulse signal having a different pulse width Q, and includes eight independent pulse generation circuits 28, each corresponding to 8 bits of the shift register 25. C28a t 2
8 b, 28 c, 28h] and
Eight independent AND circuits 29 [29a, 29b, 29c...] corresponding to each pulse generation circuit 28, respectively.
. . 29h] and one OR circuit 30.

Each pulse generation circuit 28at28bt28 c t 28
d t 28 e t 28 f t 28 From g and 28h, pulses P1. P2...
...P8 is generated.

That is, each pulse PI jP2. P3・・・・・・・・・
・For P8, the pulse width is Hn/2 n(n-1, 2,
・・・・・・・・・8) That is, H/21H/222H/2
3. . . . H/28 and the rising time is selected to be the falling time of the preceding pulse.

And each signal conversion circuit 271.272.・・・・・・
In this case, the signal of the most significant bit of the shift register 25 and the pulse signal P1 of the first pulse generation circuit 28a are sent to the first AND circuit 29a, and the signal of the next bit and the pulse signal of the second pulse generation circuit 28b are sent to the first AND circuit 29a. P2 is connected to the second AND circuit 29b, and in the same way, corresponding bit signals and pulse signals of the pulse generation circuit correspond to each other in the AND circuit 2.
8, therefore, the least significant bit signal and the pulse signal P8 of the eighth pulse generating circuit are respectively supplied to the eighth AND circuit 29h, and the respective AND circuits 29a, 29b, . . .
The output of 29h is supplied to the OR circuit 30.

Therefore, each signal conversion circuit 27□, 27□,...
. . . From each OR circuit 30 that is pressed, the shift register 2
The output of the AND circuit 29 where the signal of the 5th bit and the signal of the pulse generation circuit 28 match, that is, the corresponding pulse signal from the pulse generation circuit 28 is output.

For example, the signal of shift register 25□ is rlolloooo
oJ, the OR circuit 30 of the signal conversion circuit 271 outputs the pulse signal P1. P3 and P4 are output sequentially.

On the other hand, each control electrode 2□, 2□, 23 of the picture tube...
. . . are switching transistors T1. T2
゜T3, constant voltage VCD through...
is connected to a terminal t2 that supplies each transistor T
□.

T2. The signal conversion circuits 28a, 28b, 28c, . . . corresponding to the base of T3, . . .
The outputs of the respective OR circuits 30 are respectively supplied.

Therefore, required pulse signals with different pulse widths are obtained from each corresponding OR circuit 30 according to the level (brightness) of the signal accumulated in the shift register 25 of each stage, and these pulse signals are simultaneously generated. Each transistor T1) T2
, . . . , a constant voltage VCD is applied to each control electrode 20, 2□, . . . for a time corresponding to the signal level. is applied.

In this case, any one of the pulse signals P1 to P8 is continuously or intermittently applied to the control electrode 2 depending on the signal level, but in reality, the phosphor layer 3 on the control electrode 2 The gradation becomes possible due to the integral action of the eye when it emits light.

According to the above-mentioned structure, the phosphor layer 3 is coated on each stripe-shaped control electrode 2 arranged in a horizontal direction corresponding to the number of picture elements, and one phosphor layer 3 is applied to each phosphor layer 3 through the control electrode 2. By simultaneously applying a horizontal period of video signals and scanning the horizontally long band-shaped electron beam 5 vertically to cause the screen to emit light line-by-line, the luminance of the screen is improved, making it suitable for practical use. A picture tube using a phosphor for a low-speed electron beam is obtained, which can be used for a low-speed electron beam.

Moreover, the beam source 8 is disposed beside the fluorescent surface 4, and the band-shaped electron beam 5 is emitted in a direction along the fluorescent surface 4, and then deflected and irradiated onto the fluorescent surface 4. A flat picture tube is obtained as a whole.

Further, since the input energy of a phosphor for a low-speed variable electron beam is small, high brightness cannot be expected.

However, since the picture tube described above is configured to be viewed from the electron beam incident side (in the direction of arrow A), the brightness can be further increased.

In addition, since the vertical direction is uniformly scanned by the band-shaped electron beam, one drive circuit only needs to be provided for the control electrode 2 in the horizontal direction, and therefore the drive circuit configuration can be changed from the conventional X-Y matrix type. Compared to this, it is greatly simplified.

Furthermore, since this picture tube uses a band-shaped electron beam, it does not require beam deflection in the horizontal direction, but only in the vertical direction, making the deflection means simpler than in conventional point-sequential cathode ray tubes.

Furthermore, since the system is such that the signal is input to the fluorescent surface side rather than to the beam source side, a constant beam can always be extracted from the beam source 8.

FIGS. 5 and 6 show other embodiments of the present invention.

In this example, a phosphor layer 42 is uniformly applied to one inner surface 1a of a flat tubular body 1, for example, with a transparent conductive layer 41 interposed therebetween, thereby forming a phosphor surface 4.

This phosphor layer 42 can be used not only for low-speed electron beams but also for use with phosphors used in ordinary cathode ray tubes.

Among them, the transparent conductive layer 41 is for applying a required voltage to the fluorescent surface, and therefore, instead of this conductive layer 41, for example, a metal back layer may be formed on the fluorescent surface 4. .

Slits 4 each vertically long facing this fluorescent surface 4.
A plurality of control electrodes 44 [44,
.

44□, . . . ] are arranged at a predetermined interval from each other along the horizontal direction.

Mesh electrodes 7 are arranged on the control electrode 44 at predetermined intervals.
Furthermore, a main deflection electrode 45 is arranged on the ground surface 1b side of the tube body 1.
Place.

The main deflection electrode 45 in this case does not need to be transparent.

Note that the control electrode 44 and mesh electrode 7 can be structurally formed integrally.

For example, as shown in FIGS. 5 and 7, on one surface of an insulating substrate 47 provided with a large number of through holes 46 arranged vertically and horizontally, a plurality of through holes 46 are formed so that each slit 43 corresponds to each row of through holes 46. The control electrode 44 is integrally formed, and a conductive layer is formed on the other surface except for the through holes 46, and this conductive layer is used as the mesh electrode 7.

In this way, the control electrode 44 and the mesh electrode 7 are integrated with the insulating substrate 47 in between, and are arranged facing the fluorescent surface 4.

On the other hand, a beam source 8 and its beam source 8 emit a horizontally long strip-shaped electron beam 48 at a position beside the fluorescent surface 4, that is, at an end located in the longitudinal direction of the control electrode 44, as in FIGS. 1 and 2. A preliminary deflection electrode 14 is arranged in front.

In this configuration, a voltage of, for example, several hundred volts to several kilovolts is applied to the fluorescent surface 4 via the transparent conductive layer 41, and a voltage of, for example, several hundred volts to several kilovolts is applied to each control electrode 44□, 442, . . . in the same manner as in the above case. At the same time, a video signal accumulated for one horizontal period is applied to the beam source 8, and a band-shaped electron beam 48 from the beam source 8 is deflected to the fluorescent surface 4 side via the preliminary deflection electrode 14 and the main deflection electrode 45. Scanning is performed at a constant speed in the vertical direction (in the direction of arrow B) in synchronization with one horizontal period of the signal.

In this way, the band-shaped electron beam 48 passes through the slit 43 of the corresponding control electrode 44 in accordance with the signal, and is connected to each control electrode 44.
The fluorescent surface 4 is irradiated in a portion corresponding to the electron beam 5, and as the band-shaped electron beam 5 scans, the fluorescent surface 4 is sequentially excited to emit light in a line-sequential manner, thereby obtaining a desired image.

This image is viewed from the side opposite to the incidence of the beam 48, that is, from the direction of arrow C.

In such a configuration, as in the case of the first embodiment and FIG. 2, a flat picture tube is obtained in which the screen emits light in line-sequential manner, the luminance of light emission is improved, and one drive circuit is simplified.

In addition, in the above example, if a color phosphor surface is provided in which color phosphor layers of colors such as field, green, and blue are sequentially arranged so as to correspond to each control electrode, a special electrode for color selection can be used. It becomes possible to obtain a color image without providing any.

Furthermore, since there is no horizontal deflection distortion, it can also be applied to character displays.

Furthermore, in the above example, control electrodes in the form of stripes extending in the vertical direction are arranged in parallel in the horizontal direction, and a video signal for each horizontal period is simultaneously supplied to each control electrode, so that a long strip-shaped electron beam in the horizontal direction is In addition, a plurality of horizontally extending stripe-like control electrodes (corresponding to the number of picture elements in the vertical direction) are arranged in parallel in the vertical direction to scan one accumulated field. The video signal is read out for each vertical line divided according to the number of picture elements in the horizontal direction, and this video signal is simultaneously supplied to each control electrode, and a vertically long belt-shaped electron beam is scanned in the horizontal direction. You can also.

It is also possible to omit the mesh-like electrode 1.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the picture tube of the present invention, and FIG.
3 is a circuit diagram showing an example of a drive circuit applied to the present invention, FIG. 4 is a signal waveform diagram, and FIG. 5 is a diagram showing another embodiment of the present invention. 6 is a sectional view thereof, and FIG. 7 is a sectional view of the main part thereof. 1 is a tube body, 2 is a control electrode, 3 is a fluorescent layer, 4 is a fluorescent surface,
5 is a band-shaped electron beam.

Claims (1)

[Claims] 1. A device comprising: a plurality of control electrodes extending in one direction of the screen and arranged in parallel; a band-shaped electron beam elongated in a direction perpendicular to the direction of extension of the control electrodes; and a fluorescent surface; The band-shaped electron beam is scanned on the fluorescent surface in the direction in which the control electrode extends, and the accumulated video signal is read out for each line scanned by the band-shaped electron beam.
A picture tube in which the control electrodes are sequentially supplied line by line. 2. The picture tube according to claim 1, wherein the fluorescent surface comprises red, edge, and blue color phosphors arranged in correspondence with a plurality of control electrodes.