JPH03207181A - Driving method for plane type cathode-ray display device - Google Patents

Abstract

PURPOSE:To detect an electron beam by the entire electrode by cutting off the electron beam, which is cut off in a blanking period and radiated by a cathode, by a 2nd electrode on an anode side. CONSTITUTION:A horizontal control electrode 18 as a 1st electrode detects the electron beam emitted by the cathode 16 in the blanking period and an error signal is fed back to at least either of the horizontal control electrode 18 and a lead-out electrode 20; and its output signal is corrected to drive the electron beam while controlling it. Thus, a beam quantity detecting means is the electrode 18 which is arranged on the reverse surface side at right angles to the cathode; while this beam quantity detection electrode is applied with a potential which is positive to the the cathode, a cutoff potential is applied from the cathode to electrode on the anode side to cut off the electron beam traveling from the cathode to the anode. Consequently, the electrode on the reverse surface side of the cathode detects the quantity of the electron beam effectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a flat panel cathode ray display device for displaying characters and graphics, and in particular to a device for deflecting a plurality of electron beams emitted from a plurality of linear cathodes. The present invention relates to an improvement in the driving method of a flat panel cathode ray display device that displays a single image by connecting rusks generated by the following methods.

<Prior Art> The present applicant previously proposed a flat image display device that displays a single image by connecting rusks generated by deflecting electron beams emitted from a plurality of linear cathodes. There is.

This display device is illustrated with reference to FIGS. 1 and 2.
This display device basically includes an envelope composed of a front substrate 12, a rear substrate 14, and a side wall (not shown), and is arranged in the envelope in parallel to each other in the horizontal direction. A plurality of linear cathodes l6, a horizontal control electrode l8 formed on the inner surface of the back substrate l4 by vapor deposition or etching and provided perpendicular to the linear cathode l6, and a horizontal control electrode l8 provided immediately before the cathode l6 with the same number of wooden electrodes as the cathode l6. The extraction electrode 20 is divided in the horizontal direction, and the extraction electrode 20 and the front substrate l2
A pair of vertical deflection electrodes 22 are arranged to sandwich the cathode l6 between them, and a metal-packed phosphor is formed on the front substrate l2 to face the plurality of cathodes l6 and forms an anode. It is equipped with @24. In the illustrated example, in the pair of vertical deflection electrodes 22, electrode portions on opposite sides of adjacent pairs are formed integrally with each other. The phosphor film 24 is
It may be provided on a transparent oxide anode such as O (Int Oy: Sn02).

In FIGS. 1 and 2, only the front substrate, back substrate, and electrodes are shown to simplify the explanation, and parts such as the side wall of the envelope and the getter inside are omitted.

The eyelid pole 16 is of a so-called indirect heating type, and includes, for example, a heater wire 16A made of a thin tungsten wire coated with a heat-resistant insulating material such as alumina with a diameter of several tens of gm, and a heater wire 16A that covers the heater wire 16A. It consists of a nickel cylindrical cathode body 16B with a diameter of, for example, several tens to several hundreds of meters attached, and the outer surface of this cathode body 16B is coated with (Ba, Sr,
It is coated with an electron-emitting oxide such as Ca)O. Regardless of the presence or absence of electron emission from the cathode 16, the heater wire 16A is constantly supplied with direct current, alternating current, or pulsed current to constantly heat the cathode 16 to the electron emission temperature of 600 to 800°C.

The extraction electrode 20 has the function of extracting electrons from the cathode 16 by applying a positive potential to the cathode 16.

The vertical deflection electrode 22 focuses the electrons taken out by the extraction electrode 20, and also vertically deflects the electron beam taken out from the cathode l6 to a predetermined area of the phosphor screen provided on the front substrate l2. It has the function of deflecting and scanning. This focusing condition is achieved by applying appropriate potentials to the vertical deflection electrode 22 on both sides of the cathode l6, the horizontal control electrode l8, the extraction electrode 20, the cathode l6, and the anode, which is formed just before the cathode l6 and convex toward the anode. The optimum conditions are determined by the electron lens that serves as the mold, and the optimum conditions can be obtained by adjusting the potential applied to the electron beam or the electrode mentioned above so that the desired beam spot width is achieved at the anode surface. In addition, the fA direction condition is that a pair of vertical deflection electrodes 2 are arranged to sandwich the cathode l6.
The electron beam is set to scan a desired deflection region by applying substantially equal positive and negative sawtooth or step-like voltages that gradually increase or decrease to each of the electron beams.

The horizontal control electrode l8 is horizontally divided into a number approximately equal to the horizontal resolution of this device, and the sheet-like electrons extracted from the cathode l6 are set by setting each potential to the cutoff potential or beam emission potential. It has the function of dividing the beam bundle.

Next, the driving method and operation of the display device shown in FIGS. 1 and 2 will be explained. In this device, a set of cathode 16 and vertical deflection electrode 22 is used as a scanning electrode, and a horizontal control electrode 18 is used as a data electrode, and an arbitrary image can be created by scanning the set of scanning electrode and data electrode line-sequentially. indicate.
That is, for example, (a), (b), (c) shown in FIG.
When attempting to display an image on the screen by connecting the small areas in (d), first take out the potential of the cathode 16 corresponding to the area (a) and make it negative with respect to the potential of the electrode 20, and then Scanning the region (a) by setting the potential of the cathode 16 in the regions (b) to (d) to be approximately equal to or positive to the potential of the extraction electrode 20,
The areas (b), (c), and (d) are sequentially scanned using the same procedure. Image data is sent to the horizontal control electrode l8 in synchronization with the scanning timing of each area. That is, for example, when the area (b) is deflected and scanned in six steps (corresponding to six pixel rows), the horizontal control electrode l8 is modulated at the timing of scanning the electron beam for display.

Also, it is possible to display halftones of the image, which is
For example, by keeping the potential of the extraction electrode 20 constant and modulating the potential of the cathode l6 or the horizontal control electrode 18 with a video signal to respectively modulate the electric field distribution around the cathode 16, that is, the electron beam from the cathode l6. It is done.

(Invention or problem to be solved) However, in this way, multiple linear cathodes are used to scan small areas of the screen assigned to each cathode, and the small areas are combined to form one screen. In flat panel cathode ray display devices, the amount of electron beams emitted from each cathode varies depending on the activity of the electron radioactive material coated on the surface of the cathode, variations in the surface temperature of the cathode, and changes over time. As a result, the brightness of each display area was different, and the display quality at the joints was significantly degraded.

Several proposals have been made to prevent this. For example, (1) as shown in JP-A-56-88244 and JP-A-60-93741, in order to detect the amount of beam from each cathode, a hole is provided through which the electron beam passes. An error signal is detected by comparing the actual electron beam amount and the target electron beam amount using a beam amount detection electrode that detects the amount of the electron beam and a current detection device that detects the integrated beam amount. A method of returning to a predetermined electrode was proposed, and (2) Japanese Patent Application Laid-Open No. 60-235
As shown in Publication No. 329, the cathode tension section is extended to the outside of the effective display screen, and the beam detection electrode is also placed outside the effective display screen, and the beam amount is detected outside the effective display screen. A method has been proposed in which a predetermined electrode is controlled according to the value. Furthermore, (3) as shown in Japanese Unexamined Patent Publication No. 62-15738, two beam detection electrodes each having a through hole through which the electron beam passes are arranged within the effective screen, and the detection electrode on the anode side is placed horizontally. A method has been proposed in which the amount of electron beam is detected by setting the cutoff state during the blanking period and applying a positive potential to the detection electrode on the cathode side, and controlling a predetermined electrode according to this detected value. ing.

However, if an effective off-screen C current detection means is provided, it is difficult to ensure a sufficient amount of beam, and the size of the panel becomes large relative to the display screen, and it is also difficult to detect the amount of current at the cathode end. Moreover, since the detection means for detecting the longitudinal direction of the cathode is not provided, the effectiveness of the detected current value is low. In addition, providing a beam detection electrode increases the manufacturing cost of the device and causes beam landing errors.Additionally, applying a positive potential to this beam detection electrode causes disturbances in the electric field, so new means of correction must be taken. There are drawbacks that arise from necessity.

In the method of detecting the amount of electron beam using existing electrodes having a through-hole, the electron beam is passed through the through-hole without causing the electron beam to collide with these electrode means and generate secondary electrons that degrade the image quality. Since the electron beam is completely transmitted, the amount of beam incident on the detection means is extremely weak, and the through hole of the electrode that detects the electron beam has extremely high precision.
Therefore, it has the disadvantage that an expensive detection means is required to avoid detection errors.

Using two beam detection electrodes, applying a high negative potential to the anode side detection electrode during the blanking period cuts off the electron flow from the cathode, while applying a positive potential to the cathode side detection electrode. If the cut-off potential is not set high, electrons that have accelerated energy on the way to the detection electrode will be blocked, or they will collide with other electrodes with high energy on the way to the detection electrode. In addition, unless a high positive potential is also applied to the detection electrode on the cathode side, the negative electric field of the detection electrode on the anode side (cutoff electrode) cannot be canceled. There are disadvantages such as voltage resistance and the need for expensive control circuits.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flat panel cathode ray display device that avoids the above-mentioned drawbacks and can efficiently detect the amount of electron beams with a simple configuration and obtain images without uneven brightness.

Means for Solving the Problems> In order to solve the above problems, the present invention comprises a plurality of linear cathodes, an anode provided opposite to these linear cathodes and integrated with a phosphor. , a first electrode that is provided perpendicularly to the cathode on the opposite side of the anode to the cathode and is divided into a plurality of electrodes; In a flat panel cathode ray display device that includes at least a second electrode that blocks the emitted electron beam, the first electrode detects the electron beam emitted from the cathode during the blanking period, and the cathode and the 2
A flat plate type negative line display characterized by feeding back an error signal to at least one of the electrodes and correcting the output signal! <Operation> As described above, the beam amount detection means of the present invention is arranged perpendicularly to the cathode on the back side (opposite to the anode) of the cathode, and allows electrons to pass through. It is an existing electrode that does not have a through hole,
During the blanking period, a positive potential with respect to the cathode is applied to this beam amount detection electrode, and a cut-off potential is applied to the electrode placed closer to the anode than the cathode, thereby blocking the electron beam directed from the cathode to the wA electrode. This makes it possible to effectively detect the amount of electron beam using the electrode on the back side of the cathode.

(Embodiments) The embodiments of the present invention will be described in detail with reference to the drawings, or the specific structure of the electrode means of the flat panel cathode ray display used in the present invention is shown in FIGS. 1 and 2. The present invention improves the driving method. The method of the present invention basically includes a plurality of linear cathodes 16 and a phosphor film 2 provided opposite to these linear cathodes 16.
an anode integrated with the cathode 4, an l-th electrode provided orthogonally to the cathode l6 on the opposite side to the anode side with respect to the cathode 16 and divided into a plurality of pieces, for example, a horizontal control electrode l8, and an l-th electrode integrated with the cathode l6; On the other hand, when driving a flat panel cathode ray display device that includes at least a second electrode, for example, an extraction electrode 20, which is provided on the anode 24 and is cut off during the blanking period to block the electron beam emitted from the cathode. The electron beam emitted from the cathode 16 during the blanking period is detected by the horizontal control electrode l8, which is the first electrode, and the electron beam emitted from the cathode l6 and the first
3 and 3, in which the electron beam is controlled and driven by feeding back an error signal to at least one of the control electrode 18 and the extraction electrode 20, which are the second electrodes, and correcting the output signal. FIG. 4 shows a driving circuit used in a method of driving a display device according to an embodiment of the present invention and a timing chart of its operation.

FIG. 3 shows only the electrode means used in the method of the present invention, and the linear cathode 16 has a plurality of indirectly heated linear cathodes extending in the horizontal direction. The electrodes are a control electrode 18 and a take-out electrode 20, which are integrally provided on the back substrate side. The plurality of indirectly heated linear cathodes 16 are placed in an electron emission state by the heater power supply 26, and the uppermost cathode 16.
from the bottom cathode l6n, the extraction electrode 20
A potential lower than that of is applied and electrons are sequentially emitted. The potential of this cathode 16 is given a constant potential during the scanning period, but during the blanking period, it is temporarily set to a potential approximately equal to or higher than the potential of the extraction electrode 20 to direct the beam toward the anode. Cut off.

On the other hand, the potential of the extraction electrode 20 is held at a high level during the scanning period, and is temporarily lowered to a low level in synchronization with the cathode 16 during the blanking period. Therefore, during the scanning period, one predetermined cathode l6 is selected and the electron beam is emitted from this cathode 16 toward the anode, or during the blanking period, the same cathode l6 is used to irradiate the screen. An electron beam flows all at once toward a plurality of horizontal control electrodes 18 to which a positive potential is applied to the cathode 16.

Therefore, horizontal control electrode 18A. 18B---18M
The voltage vh obtained by converting the current output during the blanking period of each vertical scan is as shown in FIG. At voltage vh, the output part surrounded by the dashed line is due to variations in the horizontal (longitudinal) direction of the cathode l6, and the output part surrounded by the two-dot button line is due to variations in the electron beam radioactivity of each cathode l6. It is something.

The output from each horizontal control electrode l8 is connected to a current sense amplifier 30.
This voltage is then converted to a voltage and amplified by the sample/hold circuit 32. The signal is converted into a digital signal through an A/D converter 34.

This signal is stored in the memory circuit of the memory circuit/signal processing unit 36, and in order to determine and correct variations in the cathode l6, the output portion 01 shown by the dashed line in FIG. From 18M, vertical addition and averaging processing are performed, and the output is sequentially output to the comparison circuit 38, and the output portion 02 shown by the two-dot chain line is horizontally added and averaging processing, and further processing such as D/A conversion is performed. is performed and output to the horizontal control electrode voltage control section 40.

In the comparator circuit 38, the output voltage sent from the signal processing section 36 is compared with a predetermined voltage vs, and an error signal Se is obtained.
is output to the cathode voltage control circuit 28, and this control circuit 28 adds this error signal Se to the standard cathode drive voltage Vs,
Correct the driving voltage of each cathode l6. On the other hand, the horizontal control electrode drive voltage due to variations in the horizontal control electrode l8 is calculated by comparing each horizontal control electrode output signal processed by the signal processing unit 36 with a predetermined voltage (not shown) and extracting an error signal, and then The control electrode voltage controller 40 corrects the voltage and outputs it all at once. In FIG. 3, reference numeral 42 indicates an extraction electrode control circuit. 5 and 6 show a driving circuit used in a method of driving a display device according to another embodiment of the present invention and a timing chart of its operation. Since the electrode means are the same as in the previous embodiment except for the cathode 16, only the cathode system will be described and the rest will be omitted.

In this embodiment, the video signal voltage Vi is modulated by the output from the cathode voltage control circuit 44, and the cathode temperature, that is, the electron radioactivity of the cathode 16, is controlled by individually driving the heater power source of the cathode 16. It is intended to be corrected. Therefore, from the heater power supply control circuit 46, each cathode l6
A heater voltage is sequentially applied to the electrodes, and its amplitude or frequency is varied to individually control the plurality of cathodes 16 to make them emit electrons. The output from each horizontal control electrode 18 is converted to a voltage and amplified by a current sense amplifier 30 as in the previous embodiment, and converted to a digital signal through a sample/hold circuit 32 and an A/D converter 34. .

This signal is stored in the memory circuit of the memory circuit/signal processing unit 36, and in order to determine the variation in the cathode l6 and correct it, the output portion 0,° shown by the dashed line in FIG. The horizontal control electrodes 18A to 18M are added vertically, averaged, and sequentially output to the comparison circuit 38, and the output portion 02 shown by the two-dot chain line is added horizontally, averaged, and then D/A converted, etc. is processed and output to the horizontal control electrode voltage control section 40. The comparison circuit 38 compares the output voltages sequentially sent from the signal processing section 36 with a predetermined cathode heater power supply voltage Vcs, and outputs the error signal Se to the heater power supply control circuit 46, which controls the output voltages sequentially sent from the signal processing section 36 to a predetermined heater power supply voltage Vcs. By adding this error signal Ss to the voltage, variations in the radioactivity of each cathode 16 are corrected by the cathode temperature.

On the other hand, the horizontal control electrode drive voltage due to variations in the horizontal control electrode l8 is determined by comparing each horizontal control electrode signal processed by the signal processing unit 36 with a predetermined voltage (not shown), as in the previous embodiment. After the signal is extracted, it is added to the standard output voltage in the horizontal control electrode voltage control section 40, corrected in the next field, and output all at once. In addition, in the above embodiment, the electrode perpendicular to the plurality of linear cathodes is provided perpendicularly to all the cathodes, or is not limited to this, but may be divided into a plurality of parts, for example, into two parts, upper and lower. You can also monitor each of them.

Further, in the above embodiment, the cut-off electrode is the take-out electrode 20, but it is not limited to this, and it may be an electrode located close to the cathode l6, or it may be divided in the horizontal direction. It doesn't have to be. Furthermore, the linear cathode 16 may be of a directly heated type instead of an indirectly heated type, and in this case, the potential is temporarily taken out during the blanking period to be lower than the potential of the electrode 20 and higher than the potential of the horizontal control electrode 18, It is clear that a similar effect can be obtained by comparing the output from the horizontal control electrode l8 with a predetermined voltage through a memory circuit, a comparator circuit, etc., extracting an error signal, and feeding this back to the cathode potential or extraction electrode potential. be.

In addition, in the above embodiment, it is possible to simultaneously detect variations between the cathodes and variations in the longitudinal direction of the cathodes, or to detect and correct either one of them, or to add up the outputs of all control electrodes and average them. Instead of digitizing, the output may be sampled from any plurality of electrodes and corrected.

(Effects of the Invention) According to the present invention, as described above, the first electrode (the electrode opposite to the anode) and the second electrode are provided on both sides of the cathode.
The second electrode on the anode side of the display device having an electrode (anode side electrode) is cut off during the blanking period to block the electron beam emitted from the cathode, and the first electrode is cut off during the blanking period to block the electron beam emitted from the cathode. The electron beam emitted from the middle cathode is detected, an error signal is fed back to the cathode and at least one of the first and second electrodes, and the output signal is corrected. Since the electron beam can be detected by the entire electrode, a sufficient detection current can be obtained and there is no detection error, and since the detection means is located within the effective display screen, there is no need to increase the size of the panel. In addition, it is possible to correct for variations in the electron beam flow in the longitudinal direction of the cathode, and the voltage applied to the electrodes that cut off the electron beam or detect the electron beam can be applied to these electrodes or to the cathode. Because they are close together, the detection electrode can be kept low, and since the detection electrode also serves as an existing electrode, there is no disturbance of the electric field and no generation of secondary electrons, improving detection accuracy and reducing the Since the number does not increase, it can be provided at low cost.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a flat panel cathode ray display device previously proposed by the present applicant, FIG. 2 is a sectional view of the device shown in FIG. 1, and FIGS. 3 and 4 are each an embodiment of the present invention. A wiring diagram of a drive circuit implementing the method according to the present invention, an output waveform diagram of each electrode when driven by this drive circuit, and FIGS. 5 and 6 respectively show a drive circuit implementing the method according to other embodiments of the present invention. The wiring diagram and the output waveform diagram of each electrode when driven by this drive circuit are 16--linear cathode, 18--one horizontal control electrode (first electrode). 20
-----One extraction electrode (second electrode). 22------
one vertical deflection electrode, 24 - one phosphor film. 26--1--heater power supply, 28--1 cathode voltage control circuit, 3
0---1 current detection amplifier, 36 1---1 memory circuit/signal processing section, 38 11 comparison circuit.

Claims (1)

[Claims] a plurality of linear cathodes, an anode provided opposite to the linear cathode and integrated with a phosphor, and a plurality of anodes provided perpendicularly to the cathode on the opposite side of the anode side with respect to the cathode. At least a second electrode is provided on the anode side of the cathode and is cut off during a blanking period to block an electron beam emitted from the cathode. In a flat panel cathode ray display device,
Detecting an electron beam emitted from the cathode during the blanking period with a first electrode, feeding back an error signal to the cathode and at least one of the first and second electrodes, and correcting the output signal. A method for driving a flat panel cathode ray display device, characterized in that: