JP2002093347A - Cathode-ray tube and signal detection method in cathode- ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the phase difference of the electric detection signal and reference signal that are outputted corresponding to the irradiation of the elec tron beam without adopting a complicated circuit structure, and to enable extracting the necessary signal content from the detection signal with good precision. SOLUTION: The capacitor C20 for reference signal output is put adjacent to the capacitor for index signal output and made substantially the same structure. By outputting the reference signal Sref and the index detection signal Sind by practically the same method from the adjacent positions, the amplitude of each vibration can be made nearly the same size and also the phase difference between each signals can be made small. Hence the removal of the unnecessary signal content contained in the index detection signal Sind becomes easy and only the necessary index information signal can be extracted from the index detection signal Sind with good precision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube used for displaying various images and a signal detecting method for detecting a signal used for correcting an image display in the cathode ray tube.

[0002]

2. Description of the Related Art At present, image display devices (such as television receivers and various monitor devices) are equipped with cathode ray tubes (CRTs).
Cathode Ray Tube) is widely used. The cathode ray tube emits an electron beam toward a phosphor screen from an electron gun provided in the tube (inside the cathode ray tube), and deflects the electron beam electromagnetically with a deflection yoke or the like, so that the electron beam is applied to the tube surface. The scan screen is formed according to the scan.

[0003] A cathode ray tube is generally provided with a single electron gun, but in recent years, a configuration provided with a plurality of electron guns has been developed. For example, in the case of a cathode ray tube for color display, for example, two electron guns for emitting three electron beams for red (R; Red), green (G; Green) and blue (B; Blue) are provided. Are being developed. A method using a plurality of electron guns in a cathode ray tube is called a double electron gun method or the like. In a multiple electron gun type cathode ray tube, a plurality of divided screens are formed by a plurality of electron beams emitted from a plurality of electron guns, and a single screen is formed by connecting the plurality of divided screens. Image is displayed. Techniques related to the double electron gun type cathode ray tube are disclosed in, for example, Japanese Utility Model Publication No. 39-25641, Japanese Patent Publication No. 42-4928, and Japanese Patent Application Laid-Open No.
No. 17,167, and the like. According to such a cathode ray tube having a plurality of electron guns, there is an advantage that a larger screen can be achieved while shortening the depth than a cathode ray tube using a single electron gun.

[0004]

By the way, conventionally,
It is known that the display state of an image of a cathode ray tube changes depending on the usage conditions. For example, the effect of an external magnetic field such as terrestrial magnetism differs depending on the environment in which a cathode ray tube is used, so that image distortion generally called “image distortion” occurs. In this case, in the case of a cathode ray tube for color display, a color shift called “misconvergence” occurs in which the scanning position of the electron beam for each color is shifted on the tube surface. Such a change in the display state adversely affects the accuracy of the display state of the joint portion in the above-described double electron gun type cathode ray tube.

Conventionally, there is a method of correcting color misregistration and the like by using a sensor for detecting the direction of terrestrial magnetism and feeding back the detected value to a circuit system such as a deflection circuit. However, such a method has a problem that, although it is possible to correct the uniform influence of terrestrial magnetism, it is difficult to perform fine correction accompanying the influence of a complicated magnetic field environment. In addition, image distortion and color misregistration are caused not only by changes in geomagnetism but also by changes over time due to heat generated by a circuit system or a cathode ray itself. These can also be corrected by using a heat sensor or the like and feeding back the detected value to a circuit system. However, in this case, it is necessary to arrange the sensors at various positions.

Therefore, the applicant of the present invention has previously filed Japanese Patent Application No. 11-726.
No. 51 proposes a technique of outputting an electrical detection signal according to the scanning position of an electron beam and using the detection signal to correct the display state of an image. In this proposal, an electrode called an index electrode is provided in an overscan region of the electron beam in the tube, and an electric signal is output from the index electrode according to the incidence of the electron beam (hereinafter, this index is referred to as an index electrode). A signal detection method using electrodes is referred to as an "electric index method." In the electric index method, an electric signal detected at the index electrode is output to the outside of the envelope via a capacitor formed by using a part of the envelope forming the cathode ray tube. By using this electric index method, it is possible to directly detect the trajectory of scanning of the electron beam. Therefore, by using the electric index method, it is possible to cope with a change in the display state due to various factors, as compared with the conventional method of indirectly detecting the image distortion by detecting the direction and heat of the terrestrial magnetism. Also,
If the electric index method is used, the displacement of the trajectory of the electron beam at various positions can be measured, so that there is an advantage that it is possible to finely correct the display state of an image.

However, an electric (voltage) signal (hereinafter, also referred to as an "index signal") extracted by the above-described electric index method is related to a required electron beam trajectory as shown in FIG. Not only information (hereinafter also referred to as “index information”) but also various unnecessary signal components included in the anode voltage are extracted. FIG. 18 shows an example of the waveform of the index signal. The part indicated by reference numeral 202 is
It is the signal part that represents the index information that is really needed. FIG. 19 shows a signal part 2 representing index information.
02 is shown in an enlarged manner. The unnecessary signal component includes, for example, an H cycle (horizontal cycle) pulse generated from a flyback transformer section or a deflection yoke section that generates a high voltage (indicated by reference numeral 201 in FIG. 18).

Here, as shown in FIGS. 18 and 19, while the value of the horizontal period pulse signal, which is an unnecessary signal component, is, for example, 10 V (volt) or more, a pulse signal representing necessary index information is provided. Is, for example, 100 m
Only about V. As described above, if the signal value of the unnecessary signal component is much larger than the signal value of the required signal component, the SN ratio (signal-to-noise ratio) is deteriorated, which is required. There is a possibility that the retrieval accuracy of the index information may be deteriorated. When the index information is used to correct the display state of the image, the deterioration of the index information extraction accuracy adversely affects the accuracy of the correction, which is not preferable.

As a method of extracting index information with high accuracy, a method of removing an extra waveform component using a circuit such as a filter can be considered. However,
In order to accurately extract a signal using a filter circuit, there is a problem that a very complicated circuit is required. There is also a problem that the waveform of the index information changes depending on the circuit.

As another method, an electric signal is extracted from the anode voltage by means similar to the index signal, and the extracted signal is used as a reference signal. In this method, it is possible to extract only the index information by taking the difference between the reference signal and the index signal. In this method, it is necessary to adjust the amplitude and the phase so that the waveforms of the unnecessary signal components included in the index signal and the reference signal match. Regarding the amplitude, it is possible to make the output means of each signal (for example, a capacitor formed by using an envelope) substantially the same configuration, and to make them equal by adopting a method such as equalizing the capacitance used for the output. it can. On the other hand, regarding the phase, there are several factors such as a path through which a signal passes, as well as the effect of the capacitor used as the output means. In order to match the phases, a method of arranging a signal processing circuit such as a delay equalizer (which changes only the phase to keep the output constant) after outputting the signal may be considered. However, such a method has a problem that the circuit configuration becomes complicated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object the purpose of eliminating the need for a complicated circuit configuration and for comparing an electrical detection signal and a reference signal output in response to the incidence of an electron beam. It is an object of the present invention to provide a cathode ray tube and a signal detection method in the cathode ray tube which can reduce a phase difference and accurately extract a necessary signal component from a detection signal.

[0012]

A cathode ray tube according to the present invention comprises an envelope, an anode voltage section to which an anode voltage is supplied, and an electronic screen for scanning an effective screen area and an overscan area outside the effective screen. An electron gun that emits a beam and an electron beam detection unit that is provided in an overscanning area inside the envelope and outputs an electrical detection signal in response to the incidence of the electron beam are provided. The cathode ray tube according to the present invention also comprises
A first capacitor formed using a part of the envelope and configured to output a detection signal output from the electron beam detecting means to the outside of the envelope; And a second capacitor configured to output a reference signal corresponding to the anode voltage to the outside of the envelope. Here, in the cathode ray tube according to the present invention, the second capacitor has substantially the same structure as the first capacitor using a part of the envelope, and the second capacitor has the same structure as the first capacitor. Are arranged so close that the phase difference between the detection signal and the reference signal falls within a desired range.

The signal detecting method for a cathode ray tube according to the present invention comprises an envelope, an anode voltage section to which an anode voltage is supplied, and an electronic device for scanning an effective screen area and an overscan area outside the effective screen. With an electron gun that emits a beam, and outputs an electrical detection signal to the outside of the envelope according to the incidence of the electron beam that scans the overscan region,
The present invention is applied to a cathode ray tube configured to output a reference signal according to an anode voltage supplied to an anode voltage unit to an outside of an envelope. The signal detection method according to the present invention comprises:
In such a cathode ray tube, the detection signal and the reference signal are substantially the same using a part of the envelope, and from a position that is close enough that the phase difference falls within a desired range. , Output to the outside of the envelope.

In the cathode ray tube according to the present invention, the detection signal output from the electron beam detecting means is output to the outside of the envelope from the first capacitor formed using a part of the envelope. Further, a reference signal corresponding to the anode voltage is output from the envelope from the second capacitor connected to the anode voltage section. The second capacitor is formed to have substantially the same structure as the first capacitor by utilizing a part of the envelope, and the first capacitor and the second capacitor are connected to each other.
Are arranged so close that the phase difference between the detection signal and the reference signal falls within a desired range, so that the phase difference between the electrical detection signal and the reference signal causes the required signal component to Is reduced to such an extent that it can be extracted with high accuracy.

In the signal detection method for a cathode ray tube according to the present invention, the detection signal and the reference signal are substantially the same using a part of the envelope, and the phase difference is within a desired range. From a position close enough to fit inside,
Output to the outside of the envelope. As a result, the phase difference between the electrical detection signal and the reference signal is reduced to such an extent that necessary signal components can be extracted with high accuracy.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

As shown in FIGS. 1A and 1B, the cathode ray tube according to the present embodiment has a panel section 10 having a fluorescent screen 11A formed inside, and is integrated with the panel section 10. And a funnel unit 20. Funnel 20
On the left and right of the rear end, two elongated neck portions 30L and 30R each containing a built-in electron gun 31L and 31R are formed. In this cathode ray tube, a panel portion 10, a funnel portion 20, and neck portions 30L and 30R form an overall appearance of two funnels. The overall shape that forms the cathode ray tube is also called an "envelope". The panel section 10 and the funnel section 20 have their respective openings fused to each other, so that a high vacuum state can be maintained inside. A phosphor pattern that emits light in response to the incidence of an electron beam is formed on the phosphor screen 11A. The surface of the panel section 10 is an image display surface (tube surface) 11B on which an image is displayed by emission of the fluorescent screen 11A.

The components of the envelope such as the panel section 10 and the funnel section 20 are mainly made of a glass material or the like. The envelope is provided with a later-described index signal output capacitor C10 and a reference signal output capacitor C20 (FIG. 3). In FIG. 1, only the index signal output capacitor C10 is shown, and the reference signal output capacitor C20 is not shown. The index signal output capacitor C10 corresponds to one specific example of the first capacitor in the present invention, and the reference signal output capacitor C20 corresponds to one specific example of the second capacitor in the present invention.

Inside the cathode ray tube, there is arranged a color selection mechanism 12 made of a thin metal plate arranged so as to face the phosphor screen 11A. The color selection mechanism 12 is also called an aperture grill or a shadow mask depending on the type of the color selection mechanism. The color selection mechanism 12 has an outer periphery supported by a frame 13 and a support spring 1 provided on the frame 13.
4 is attached to the inner surface of the panel unit 10.

The funnel section 20 has an anode voltage HV
Terminal (anode button) 24 for applying voltage
(FIG. 6) (not shown in FIG. 1). Deflection yokes 21L, 21R and convergence yokes 32L, 32R are attached to an outer peripheral portion from the funnel portion 20 to each of the neck portions 30L, 30R.
The deflection yokes 21L and 21R deflect the electron beams 5L and 5R emitted from the electron guns 31L and 31R. Convergence yoke 32L, 32R
Are for performing convergence (concentration) of the electron beams for each color emitted from each of the electron guns 31L and 31R.

The fluorescent screen 1 of the panel section 10 from the neck section 30
The inner peripheral surface reaching 1A is covered with a conductive internal conductive film 22. The internal conductive film 22 includes an anode terminal 24
(FIG. 6), and is electrically connected to the anode terminal 24.
The anode voltage HV is applied via the. The outer peripheral surface of the funnel portion 20 is covered with a conductive external conductive film 23.

The electron guns 31L and 31R are not shown,
Three cathodes (hot cathodes) for R (Red), G (Green) and B (Blue), a heater for heating each cathode, and a plurality of grid electrodes disposed in front of the cathodes, respectively. have. In the electron guns 31L and 31R, the cathodes are heated by the heater, and the cathode drive voltage having a magnitude corresponding to the video signal is applied, so that the amount of thermoelectrons corresponding to the video signal is emitted. ing. The grid electrode forms an electron lens system when an anode voltage HV, a focus voltage or the like is applied, and exerts a lens function on an electron beam emitted from a cathode. The grid electrode performs convergence of individual electron beams emitted from the cathode by its lens function, and also controls emission amount of the electron beam and acceleration control. The electron beams for each color emitted from the electron guns 31L and 31R pass through the color selection mechanism 12 and the like, and pass through the fluorescent screen 11R.
A is irradiated to the phosphor of the corresponding color of A.

Here, referring to FIGS. 1B and 2, an outline of an electron beam scanning method in the present cathode ray tube will be described. The cathode ray tube has an electron gun 31 arranged on the left side.
The electron beam 5L from L draws about the left half of the screen, and the electron beam 5R from the electron gun 31R arranged on the right draws the right half of the screen. Then, the ends of the divided screens formed by the left and right electron beams 5L and 5R are partially overlapped and joined to form a single screen SA as a whole and display an image. I have. Therefore, the central portion of the entire screen SA is an area OL where the left and right divided screens overlap (overlap). The fluorescent screen 11A in the overlapping area OL is provided with the respective electron beams 5L and 5L.
R will be shared.

In the scanning method shown in FIG. 1B, so-called line scanning (main scanning) is performed in the horizontal direction, and so-called field scanning is performed from top to bottom in the vertical deflection direction. In the scanning example shown in FIG. 1B, with respect to the electron beam 5L on the left side, the line scan is directed from right to left in the horizontal deflection direction (X2 direction in FIG. 1A) when viewed from the display surface side of the image. Have gone. On the other hand, for the right electron beam 5R, line scanning is performed from left to right (X1 direction in FIG. 1A) in the horizontal deflection direction when viewed from the image display surface side. Therefore, in the scanning example of FIG.
As a whole, line scanning by each of the electron beams 5L and 5R is performed in the opposite direction from the center of the screen to the outside in the horizontal direction, and the field scanning is performed from top to bottom like a general cathode ray tube. Will be done. In this scanning method, each line scanning by the electron beams 5L and 5R can be performed from the outside of the screen toward the center of the screen in a direction opposite to that of FIG.

The scanning method shown in FIG. 2 is such that the line scanning and the field scanning by the electron beams 5L and 5R are exactly reversed from the scanning method shown in FIG. 1B. This scanning method is also called a vertical scanning method because line scanning is performed in the vertical direction.
In the scanning example shown in FIG. 2, line scanning by each of the electron beams 5L and 5R is performed from top to bottom (Y direction in FIG. 2). On the other hand, the field scan is performed using the electron beam 5 on the left side.
L is viewed from right to left as viewed from the display surface side of the image (FIG. 2).
X2 direction), and the right electron beam 5R is viewed from left to right (X1 in FIG. 2) when viewed from the image display surface side.
Direction). Therefore, in the scanning example of FIG. 2, the field scanning by the electron beams 5L and 5R is performed in the opposite directions from the center of the screen outward in the horizontal direction as a whole. In this scanning method, the field scanning by the electron beams 5L and 5R can be performed from the outside of the screen toward the center of the screen in a direction opposite to that of FIG.

In the tube of the present cathode ray tube, an overscan area (overscan) area OS of the electron beams 5L and 5R at a joint side (substantially the center of the entire screen) of the adjacent left and right divided screens has a rectangular flat plate. An index electrode 70 is provided at a position facing the fluorescent screen 11A. It can be said that the index electrode 70 is provided at a position corresponding to the overlapping area OL in the tube. In the cathode ray tube, an index electrode 7 is further provided.
A beam shield 27 serving as a shielding member for the electron beams 5L and 5R is arranged between the pixel 0 and the phosphor screen 11A. Although the figure shows an example of a structure in which the beam shield 27 has a V-shape, the shape of the beam shield 27 is not limited as long as it can shield the electron beams 5L and 5R. There may be. Beam shield 2
Reference numeral 7 denotes electron beams 5L, 5 which have overscanned the overscanning area OS.
It has a function of blocking the electron beams 5L and 5R so that R does not reach the phosphor screen 11A and emit light carelessly. The beam shield 27 is, for example, a color selection mechanism 1
It is erected using a frame 13 supporting the base 2 as a base. The beam shield 27 is electrically connected to the internal conductive film 22 via the frame 13. Thereby, the anode voltage HV is supplied to the beam shield 27.

In the present embodiment, the overscanning area is an area outside each scanning area of the electron beams 5L and 5R forming an effective screen in each scanning area of the electron beams 5L and 5R. Say. In FIG.
The area SW1 is an effective screen on the phosphor screen 11A in the horizontal direction of the electron beam 5R, and the area SW2 is an effective screen on the phosphor screen 11A in the horizontal direction of the electron beam 5L.

The index electrode 70 is connected to the electron beam 5
It has a function of outputting an electrical detection signal according to the incidence of L, 5R. As shown in FIG.
As shown in (A), a plurality of notched holes 71 having, for example, an inverted triangular shape are provided at equal intervals in the longitudinal direction. The index electrode 70 is made of a conductive material such as a metal, and is, for example, provided on the frame 13 via an insulator (not shown). The index electrode 70 is electrically connected to one end of the resistor R1. The other end of the resistor R1 is electrically connected to a portion (for example, the frame 13) to which an anode voltage is supplied. Therefore, the anode voltage HV is supplied to the index electrode 70 via the resistor R1. The index electrode 70 is electrically connected to an internal electrode 42 of a later-described index signal output capacitor C10 via a lead wire 26. In the tube, a stray capacitance is usually generated between the index electrode 70 and the beam shield 27, between the index electrode 70 and the internal conductive film 22, and the like. Note that the shape and arrangement of the cutout holes provided in the index electrode 70 are not limited to those shown in FIG.

When the overscanned electron beams 5L and 5R enter the index electrode 70, the potential at the index electrode 70 drops more than usual. In the present cathode ray tube, this voltage-dropped signal is used as an index detection signal as an index signal output capacitor C.
It is guided out of the tube via 10 and is mainly used for correcting the image state.

In the case of the vertical scanning method, for example, FIG.
Index electrode 70A having a structure as shown in FIG.
Is provided. The longitudinal direction of the index electrode 70A is the line scanning direction (Y direction) of the electron beams 5L and 5R.
A first cutout hole 131 having a rectangular shape provided to be perpendicular to the first direction, and is provided so as to be oblique to the field scanning direction (X1, X2 direction in FIG. 2) of the electron beams 5L, 5R. Elongated second cutout hole 132
And A plurality of the first notch holes 131 and the second notch holes 132 are alternately arranged.
In the example of FIG. 10A, both ends of the index electrode 70A have a structure in which the first cutout holes 131 are arranged. In the index electrode 70A, adjacent ones of the first cutout holes 131 are arranged at equal intervals. As for the second cutout holes 132, adjacent ones are arranged at equal intervals.
Note that the shape and arrangement of the cutout holes provided in the index electrode 70A are not limited to those shown in FIG.

FIGS. 3 to 5 show the structure of the index signal output capacitor C10 and the reference signal output capacitor C20. The index signal output capacitor C10 and the reference signal output capacitor C20 are connected to the panel unit 10 and the funnel unit 20.
It is formed by using a part of a component having a dielectric property in an envelope such as the above as a dielectric.

Index signal output capacitor C10
Is for outputting the electrical index detection signal S _ind generated by the index electrode 70 to the outside of the envelope. The index signal output capacitor C10 includes an index signal output external electrode 41 provided on the outside of the tube, an index signal output internal electrode 42 provided on the inside of the tube, and a dielectric component such as the funnel 20. Dielectric part 4 using part of 20A
And 3. As shown in FIG. 3, the external electrode 41 and the internal electrode 42 are arranged to face each other with the dielectric part 43 interposed therebetween.

The index signal output external electrode 41 is
For example, as shown in FIG.
Does not partially cover the external conductive film 23, that is,
The external conductive film 23 is provided with a region 23A which is electrically insulated and provided in the region. External electrode 41
Is the index detection signal S _ind as shown in FIG.
Is electrically connected to an output terminal 61 for outputting the same. The index detection signal S output to the output terminal 61
_ind is input to a signal extraction circuit 50 (FIG. 7) described later. On the other hand, as shown in FIG. 4B, the index signal output internal electrode 42
Not to partially cover the internal conductive film 22, that is, to form a region 22A electrically insulated from the internal conductive film 22,
It is provided in that area. The internal electrode 42
It is electrically connected to the index electrode 70 via the lead wire 26. The external electrode 41 and the internal electrode 42
As shown in FIGS. 4A and 4B, for example, they are formed in a square shape having the same size. The shapes of the external electrode 41 and the internal electrode 42 are not limited to a square shape, but may be other shapes (for example, a circular shape). Further, the sizes of the external electrode 41 and the internal electrode 42 do not necessarily have to be the same.

Reference signal output capacitor C20
Is for outputting the reference signal _Sref to the outside of the envelope. The reference signal _Sref is a signal used to extract a required index information signal S2 from the index detection signal _Sind , as described later. Reference signal output capacitor C
20 is an index signal output capacitor C substantially.
It has the same structure as 10. That is, similarly to the index signal output capacitor C10, the reference signal output capacitor C20 includes a reference signal output external electrode 44 provided outside the tube, a reference signal output internal electrode 45 provided inside the tube, And a dielectric portion 46 using a part of the dielectric component 20A such as the funnel portion 20. As shown in FIG. 3, the external electrode 44 and the internal electrode 45 are arranged to face each other with the dielectric portion 46 interposed therebetween.

The reference signal output external electrode 44 is
For example, as shown in FIG.
Does not partially cover the external conductive film 23, that is,
The external conductive film 23 is formed in a region 23B which is electrically insulated and provided in the region. External electrode 44
Is electrically connected to an output terminal 62 for outputting a reference signal _Sref , as shown in FIG.
The reference signal S _ref output to the output terminal 62 is
The signal is input to a signal extraction circuit 50 described later. On the other hand, as shown in FIG. 4B, the reference signal output internal electrode 45 does not partially cover, for example, the funnel portion 20 with the internal conductive film 22, that is, is electrically connected to the internal conductive film 22. An insulated region 22B is formed and provided in that region. The internal electrode 45 is electrically connected to an anode voltage section (for example, the frame 13 (FIG. 1) or the like) to which the anode voltage HV is supplied via the lead wire 28. As a result, the anode voltage HV is supplied to the reference signal output internal electrode 45 via the lead wire 28, and the reference signal S using the anode voltage HV is supplied from the reference signal output capacitor C20.
_ref is output. External electrode 44 and internal electrode 45
Are formed, for example, in a square shape having the same size as shown in FIGS. However, the shape of the external electrode 44 and the internal electrode 45 is not limited to a square shape, and may be another shape (for example, a circular shape). Further, the size of the external electrode 44 and the size of the internal electrode 45 do not necessarily have to be the same.

In FIGS. 3 and 4, the index signal output external electrode 41 and the reference signal output external electrode 44 are provided in the insulating regions 23A and 23B formed at different positions. As shown in FIG. 5A, the two external electrodes 41 and 44 may be provided in the common insulating region 23C. Each internal electrode 4
The same applies to the internal electrodes 42 and 45.
Is, as shown in FIG. 5B, a common insulating region 22C.
It may be provided inside. Also, in the illustrated example,
Although each of the insulating regions has a rectangular shape, the shape of each of the insulating regions may be another shape (for example, a circular shape).

Here, it is desirable that the reference signal output capacitor C20 is formed so that its capacitance is substantially the same as that of the index signal output capacitor C10. Each signal output capacitor C1
By making the capacitances of 0 and C20 almost the same, the reference signal _Sref and the index detection signal S _i
The waveform amplitude and frequency characteristics of the unnecessary signal component included in _nd become very close. As a result, in the signal extraction circuit 50 described later, it becomes easy to remove unnecessary signal components included in the index detection signal S _ind . The capacitances of the output capacitors C10 and C20 can be made substantially the same by adjusting, for example, the size of both electrodes. In the present embodiment, the structure of the reference signal output capacitor C20 and the structure of the index signal output capacitor C10 are substantially the same, so that the respective capacitances can be easily matched.

FIG. 6 shows each signal output capacitor C10,
It is a figure for explaining the formation position of C20, and has shown the state where this cathode ray tube was seen from the back. As shown in FIG. 6, the anode terminal 24 is provided, for example, slightly above the center of the rear part of the cathode ray tube. An anode voltage HV is supplied from the anode terminal 24 into the tube.
Each of the signal output capacitors C10 and C20 has a phase difference between the reference signal _Sref and the unnecessary signal component included in the index detection signal _Sind within a desired range (in the subsequent signal extraction circuit 50 (FIG. 7), It is desirable that the index information detection signal Sind is disposed so close to the index detection signal S _{ind as} to fall within a range in which the index information detection signal S2 can be extracted with required accuracy. Normally, the closer the formation positions of the signal output capacitors C10 and C20 are, the smaller the phase difference between the reference signal _Sref and the unnecessary signal component included in the index detection signal _Sind for the reason described later. . For example, it is assumed that the index signal output capacitor C10 is formed at a position 20-1 substantially at the center of the upper part of the cathode ray tube. In this case, the reference signal output capacitor C20 is placed at a position distant from the position 20-1 (for example, at position 2 below the cathode ray tube).
0-3), position 2 adjacent to position 20-1
It is desirable to provide 0-2 in order to solve the problem of the phase difference.

FIG. 7 shows a configuration example of a signal extraction circuit for extracting the index information signal S2 from the index detection signal S _ind using the reference signal S _ref . The signal extraction circuit 50 outputs the index detection signal S
Index signal output circuit 5 for amplifying and outputting _ind
1 and a reference signal output circuit 52 for amplifying and outputting the reference signal _Sref . The signal extraction circuit 50 also calculates the difference between the index detection signal S _ind amplified by the output circuit 51 and the reference signal S _ref amplified by the output circuit 52, and calculates an index information signal included in the index detection signal S _ind. It has a difference circuit 53 that outputs S2. The difference circuit 53 is connected to an output terminal 63 for outputting the index information signal S2. Index information signal S
2 is input to an index signal processing circuit 105 (FIG. 8) described later via an output terminal 63.

The output circuit 51 is a signal amplification amplifier AM.
P1 and an input resistance Ri1 and an input capacitance Ci1 of the amplifier AMP1. The input terminal of the amplifier AMP1 is connected to the output terminal 61, and receives the index detection signal S _ind . Amplifier AM
The output terminal of P1 is connected to one of the input terminals of the difference circuit 53. One end of the input resistance Ri1 and one end of the input capacitance Ci1 are connected between the output terminal 61 and the input terminal of the amplifier AMP1. Input resistance Ri1 and input capacitance C
The other end of i1 is grounded.

The output circuit 52 includes an amplifier AM for signal amplification.
P2 and an input resistance Ri2 and an input capacitance Ci2 of the amplifier AMP2. The output circuit 52 further has an adjusting capacitor C3 for adjusting the signal waveforms of the index detection signal S _ind and the reference signal S _ref . The input terminal of the amplifier AMP2 is connected to the output terminal 62 via the adjustment capacitor C3, and the reference signal _Sref is input via the adjustment capacitor C3. The output terminal of the amplifier AMP2 is
It is connected to another input terminal of the difference circuit 53.
One ends of the input resistance Ri2 and the input capacitance Ci2 are connected between the adjustment capacitor C3 and the input terminal of the amplifier AMP2. The other ends of the input resistance Ri2 and the input capacitance Ci2 are grounded.

By the way, usually, the output capacitor C1
0, C20, the waveform amplitude of the unnecessary signal component included in the index detection signal S _ind and the waveform amplitude of the reference signal _Sref are equal to the output capacitor C1.
0 and C20 are different depending on the difference in capacitance. Therefore, in order to extract a required signal component (index information signal S2) from the difference between the index detection signal S _ind and the reference signal S _ref , it is necessary to match the waveform intensities of the signal components. The intensity of the waveform can be adjusted by, for example, adjusting the size of the external electrodes 41 and 44 of the signal output capacitors C10 and C20, or connecting an amplitude adjustment capacitor and an amplifier circuit to the output side of each signal output capacitor C10 and C20. It is possible to adjust by providing.

In the signal extraction circuit 50, each amplifier AM
P1, AMP2 and adjustment capacitor C3 have a function of adjusting such a waveform amplitude. Thus, by matching the waveform amplitude of the unnecessary signal component included in the index detection signal S _ind with the waveform amplitude of the reference signal _Sref , the index information signal S2 can be output from the difference circuit 53 satisfactorily. In the circuit example shown in FIG. 7, the amplifier for adjustment is provided in both the output circuit 51 on the index signal side and the output circuit 52 on the reference signal side, but the amplifier is provided in only one of the circuits. You may do it. Adjustment capacitor C
3 may be provided not in the output circuit 52 on the reference signal side but in the output circuit 51 on the index signal side. Alternatively, a capacitor for adjustment may be provided in both circuits.

FIG. 8 shows a signal processing circuit of the present cathode ray tube. This cathode ray tube is analog / digital (A / D)
A converter 101, a memory 102, digital / analog (D / A) converters 103L and 103R, and a modulator 104
L, 104R and video amplifier VAMP-L, VAMP
-R. The cathode ray tube further includes an index signal processing circuit 105 and a timing generator 10.
6, a convergence circuit 107, and a deflection circuit 108.

The A / D converter 101 performs A / D conversion on the input video signal SV. The memory 102
This is for temporarily storing the video signal SV that has been A / D converted by the A / D converter 101. Memory 10
2 is constituted by, for example, a line memory or a field memory, and stores an input video signal in, for example, a line unit or a field unit. The reading and writing operations of signals in the memory 102 are controlled by a memory controller (not shown).

The D / A converter 103L has a memory 102
Of the video signal SV stored in the image signal SV, a signal necessary for drawing about the left half of the screen is input. On the other hand, to the D / A converter 103R, of the video signal SV stored in the memory 102, a signal necessary for drawing approximately the right half of the screen is input.
Each of the D / A converters 103L and 103R performs D / A conversion on the input signal. The modulator 104L is a D / A converter 1
The luminance modulation based on the given modulation signal S3L is performed on the video signal output from the 03L. The modulator 104R performs luminance modulation on the video signal output from the D / A converter 103R based on the given modulation signal S3R. The video amplifiers VAMP-L and VAMP-R are respectively connected to the modulator 104.
The video signals after the luminance modulation output from the L and 104R are amplified and output to the electron guns 30L and 30R.

The index signal processing circuit 105 receives the index information signal S 2 output from the difference circuit 53 of the signal extraction circuit 50. The index signal processing circuit 105 calculates the
Modulation signals S3L and S3R for performing luminance modulation control at a joint portion between the left and right divided screens and a correction signal S4 for performing correction of image distortion and the like are output. The timing generator 106 includes an A / D converter 101 and a memory 10 based on the input synchronization signal SS.
2. A timing signal is output to each of the D / A converters 103L and 103R and the index signal processing circuit 105. The convergence circuit 107 controls the convergence yokes 32L and 32R based on the correction signal S4 from the index signal processing circuit 105. The deflection circuit 108 controls the deflection yokes 21L and 21R based on the correction signal S4 from the index signal processing circuit 105.

Next, the operation of the cathode ray tube configured as described above will be described.

The A / D converter 101 (FIG. 8) performs A / D conversion on the input video signal SV. A / D converter 101
The video signal digitized by the above is stored in the memory 102 for each line or each field, for example, under the control of a memory controller (not shown).

Here, as an example, each electron beam 5
H / 2 (1H is one horizontal scanning period) depending on L and 5R
When the left and right divided screens are horizontally scanned in opposite directions from the center of the screen toward the outside of the screen (FIG. 1).
(B)) will be described. The 1H video signal written in the memory 102 is divided into H / 2 under the control of a memory controller (not shown). Among the divided signals, the signal for the divided screen on the left is read out in the opposite direction to that at the time of writing under the control of a memory controller (not shown) and input to the D / A converter 103L. Among the divided signals, the signal for the right divided screen is read out in the same direction as that at the time of writing under the control of a memory controller (not shown) and input to the D / A converter 103R.
The D / A converter 103L converts the reverse-read H / 2 left split screen signal into an analog signal and outputs the analog signal to the modulator 104L. The D / A converter 103R converts the signal for the divided screen on the right side of H / 2 read in the same direction as at the time of writing into an analog signal and outputs the analog signal to the modulator 104R.

Each of the modulators 104L and 104R applies a modulation signal S3L and S3R to the input video signal, respectively.
A signal subjected to luminance modulation based on the video amplifier VAM
Output to PL and VAMP-R. Each video amplifier VA
The signals input to MP-L and VAMP-R are amplified to predetermined levels, respectively, and applied as cathode drive voltages to cathodes (not shown) arranged inside each of the electron guns 31L and 31R. Thereby, each electron gun 31
Each of the electron beams 5L and 5R is emitted from L and 31R.
The cathode ray tube according to the present embodiment is capable of displaying a color image. Actually, each electron gun 31L, 31R is provided with a cathode for each color of R, G, B, and each electron gun 31L. , 31R emit an electron beam for each color. The beam current of the electron beam for each color is controlled independently for each color, and the luminance and chromaticity are adjusted.

The left electron beam 5L emitted from the electron gun 31L and the right electron beam 5R emitted from the electron gun 31R pass through the color selection mechanism 12 and irradiate the fluorescent screen 11A. At this time, the electron beams 5L, 5
R performs convergence by the electromagnetic action of the convergence yokes 32L and 32R, respectively.
It is deflected by the electromagnetic action of the deflection yokes 21L, 21R. Thus, the entire surface of the fluorescent screen 11A is scanned by the electron beams 5L and 5R, and the tube surface 11B of the panel unit 10 is scanned.
, A desired image is displayed in the screen SA (FIG. 1). More specifically, by the electron beam 5L on the left side,
About the left half of the screen is drawn, and about the right half of the screen is drawn by the right electron beam 5R. And
The left and right divided screens formed by the scanning of the electron beams 5L and 5R are joined so that the ends thereof partially overlap, thereby forming a single screen SA as a whole.

When the electron beams 5L and 5R scan the overscanning area OS and enter the index electrode 70, a voltage drop occurs at the index electrode 70.
A signal corresponding to the voltage drop is an index detection signal S
_{as ind} , the index signal output capacitor C10
It is output outside the tube via (FIG. 3). The index detection signal S _ind is _supplied to the signal extraction circuit 5 via the output terminal 61.
0 is input to the index signal output circuit 51 (FIG. 7). On the other hand, the reference signal output capacitor C20
From FIG. 3, a reference signal _Sref according to the anode voltage HV is output. The reference signal S _ref is
The signal is input to the reference signal output circuit 52 (FIG. 7) of the signal extraction circuit 50 via the output terminal 62.

The index signal output circuit 51 amplifies the input index detection signal S _ind and outputs it to the difference circuit 53 (FIG. 7). The reference signal output circuit 52 amplifies the input reference signal _Sref and outputs it to the difference circuit 53. At this time, the index signal output circuit 51 and the reference signal output circuit 52
In, adjustment is performed to match the waveform amplitude of the unnecessary signal component included in the index detection signal S _ind with the waveform amplitude of the reference signal _Sref . Difference circuit 53
_Removes unnecessary signal components included in the index detection signal S _ind by taking the difference between the input index detection signal S _ind and the reference signal S _ref ,
Only necessary signal components (index information signal S2) are extracted and output. The index information signal S2 output from the difference circuit 53 is input to the index signal processing circuit 105 via the output terminal 63.

The index signal processing circuit 105 analyzes the scanning positions of the electron beams 5L and 5R based on the input index information signal S2, and corrects image distortion based on the analysis result. Is output. The convergence circuit 107 controls the convergence yokes 32L and 32R based on the correction signal S4 from the index signal processing circuit 105. In addition, the deflection circuit 108 includes the index signal processing circuit 10
5 based on the correction signal S4 from the deflection yoke 21L, 2L.
Control 1R. Thereby, the scanning position of the electron beam is corrected, and image distortion and the like are corrected. The index signal processing circuit 105 also controls the modulation signals S3L, S3L for controlling the modulation of the luminance at the joint between the left and right divided screens based on the input index information signal S2.
Output S3R. The modulators 104L and 104R output D /
The luminance modulation based on the modulation signals S3L and S3R is performed on the video signals output from the A converters 103L and 103R. Thereby, the correction of the luminance at the joint portion between the left and right divided screens is performed. In this way, the left and right split screens are displayed in a manner that they are properly joined in terms of position and brightness.

Next, data obtained by analyzing the detection signal from the index electrode 70 will be described with reference to FIGS. 9A to 9E.

FIGS. 9A to 9E show an example of the structure of the index electrode 70 and the waveform of an electrical detection signal output from the index electrode 70. FIG. In this cathode ray tube, by providing the cutout hole 71 in the conductive index electrode 70, it is possible to detect the scanning positions of the electron beams 5L and 5R in the horizontal direction (line scanning direction) and the vertical direction (field scanning direction). ing. In this figure, only the right electron beam 5R will be described, but the same applies to the left electron beam 5L. Here, for the electron beam 5R, the line scanning is performed from left to right at the center of the screen, and the field scanning is performed from top to bottom (Y direction in FIG. 1) (FIG. 1).
(B)) will be described.

In FIG. 9A, a trajectory BY is a trajectory of a horizontal scanning start point of the electron beam 5R before image correction. In the example of this figure, the trajectory BY of the electron beam 5R before image correction is a pincushion type (pin cushion type) in which the center in the horizontal direction is contracted and the upper and lower parts in the horizontal direction are elongated. Has become. Also, the trajectory BY0
Is the electron beam 5 when the proper image correction is performed.
It is the trajectory of the horizontal scanning start point of R. In the present embodiment, in order to detect the position of the electron beam 5R, in the overscanning region OS provided with the index electrode 70,
A plurality of electron beams B1 to B5 for position detection in the horizontal direction
Through at least the number corresponding to the number of the cutout holes 71. In the following, a description will be given assuming that the electron beam passes almost in the middle of the plurality of cutout holes 71, for example, as shown in the illustrated electron beams B10 to B50 when the appropriate image correction is performed. Note that the number of electron beams passing through the index electrode 70 for position detection is not limited to the same number as the number of the cutout holes 71.

When the electron beams B1 to B5 for position detection pass through the index electrode 70, a detection signal having two pulse signals is output as shown in FIG. 9B. The two pulse signals are signals output when the electron beams B1 to B5 pass through the electrode portions at both ends of the cutout hole 71. The time (th1 to th5) from the scanning start point of the electron beams B1 to B5 (time t = 0) to the edge portion of the first pulse signal represents the state of the amplitude of horizontal deflection and image distortion. When all the times reach a certain time th0, the horizontal deflection is completely corrected.

FIG. 9C shows a detection signal output after the horizontal deflection has been corrected. As described above, when the electron beams B1 to B5 pass through the portion of the index electrode 70 where the cutout holes 71 are provided, two pulse signals are output. tv1 to tv5) are cutout holes 71
Corresponding to the vertical direction (vertical direction). Therefore, when the pulse intervals (tv1 to tv5) all reach the fixed time tv0, the vertical amplitude and the linearity are adjusted, and the vertical deflection is completely corrected. When both the horizontal deflection and the vertical deflection are corrected, as shown in FIG. 9D, the time from the scanning start point (t = 0) to the edge portion of the first pulse signal is constant time th0, A detection signal whose two pulse intervals are the predetermined time tv0 is output. At this time, as shown in FIG. 9E, in the index electrode 70, the electron beams B1a to B5a in the ideal state pass through almost the center of the plurality of cutout holes 71.

In the analysis of the pulse signal of the detection signal output from the index electrode 70, the index signal processing circuit 105 (FIG. 8) actually analyzes the index information signal S2 obtained through the signal extraction circuit 50. This is done by: The index signal processing circuit 105 calculates the correction signal S based on the analysis of the index information signal S2.
4 is output. The deflection circuit 108 controls the deflection yoke 21R based on the correction signal S4. As a result, the scanning position of the electron beam 5R is controlled, and image correction is performed so that image distortion and the like are corrected.

The cathode ray tube is capable of color display, and there are electron beams 5R to be adjusted for each color of R, G, and B, but an image is formed for each of R, G, and B colors. By controlling the data, the convergence correction can be automated. By performing such automatic control, for example, FIG.
It is possible to automatically correct the pincushion-type image distortion such as the locus BY shown in FIG.

Since the above description is for the right electron beam 5R, about the right half screen of the entire screen area is corrected, but the left electron beam 5L is similarly corrected. By doing so, the screen on the left is corrected. By correcting the left and right split screens in this manner, the left and right split screens are displayed in a state of being appropriately joined together. The index electrode 70 is
Since only one is provided, the electron beams 5L, 5R
Cannot be detected completely simultaneously. Therefore, the right and left split screens cannot be corrected at the same time. For example, it is necessary to alternately detect the scanning positions of the electron beams 5L and 5R for each line operation or field scan and to correct the electron beams 5L and 5R alternately. Thus, the left and right split screens can be corrected.

Next, the detection operation of the index signal in the case of the vertical scanning method (FIG. 2) will be described.

FIGS. 10A to 10G show the structure of the index electrode 70A applied when the vertical scanning method shown in FIG. 2 is used and the waveform of the detection signal output from the index electrode 70A. An example is shown. In FIGS. 10A to 10G, the left side of the paper corresponds to the upper side of the screen, and the right side of the paper corresponds to the lower side of the screen. In the index electrode 70A, FIG.
Assuming that two electron beams eB1 and eB2 for position detection have passed in the line scanning direction as shown in (1), detection signals as shown in FIGS. 10B and 10C are output, respectively. 10B and 10C, the amplitude and position of the line scanning of the electron beams eB1 and eB2 can be detected from the periods T _T and T _B shown at both ends. The irregularities of the periods T ₁₃ , T ₃₅ , T ₅₇ , and T ₇₉ during which the electron beams eB 1 and eB 2 pass through the adjacent notches 131 are as follows:
It indicates whether linearity of line scanning is good or bad. The positions of the pulse signals (pulses P1 to P4 in FIG. 10C) generated when the electron beams eB1 and eB2 pass through the oblique cutout 132 indicate information on the amplitude of the field scan. ing.

FIG. 10E shows a detection signal output from the index electrode 70A when the electron beam eB3 having a pincushion type image distortion passes as shown in FIG. 10D. FIG. 10F shows a detection signal output from the index electrode 70A when the electron beam eB4 having the barrel-shaped image distortion passes as shown in FIG. 10D. FIG. 10 (G) shows a detection signal output when there is an electron beam eB5 passing through a substantially central portion in the longitudinal direction of the index electrode 70A as shown in FIG. 10 (D). As can be seen from these figures, a detection signal having a different waveform is output from the index electrode 70A in accordance with the scanning position and scanning timing of the passing electron beams 5L and 5R. Therefore, for example, the electron beams 5L and 5R are not
By observing and analyzing the phase of the pulse signal train when passing through 1, 132, the trajectory of each electron beam 5L, 5R on index electrode 70A can be estimated.

The analysis of the phase of the pulse signal train of the detection signal output from the index electrode 70A is performed by the index signal processing circuit 105 (FIG. 8) in the same manner as in the case of using the index electrode 70 of FIG. This is performed by analyzing the index information signal S2 obtained via the circuit 50.

Note that the shape of the cutout holes provided in the index electrodes 70 and 70A is not limited to that shown in the drawings.
Other shapes may be used. For example, the index electrode 7
The shape of the cutout hole 71 provided at 0 is not limited to an inverted triangular shape, and various shapes of cutout holes such as a rhombus, a circle, and an ellipse can be used. Further, the number of cutout holes provided in the index electrodes 70 and 70A is not limited to the illustrated number, and may be configured to be larger or smaller than the illustrated number. However,
When the image distortion is more complicated and includes higher-order components, it is considered that it is necessary to increase the number of cutout holes to increase the detection accuracy. Further, the intervals between the notch holes do not necessarily have to be equal. Further, in the above description, the scanning positions of the electron beams 5L, 5R are detected by one index electrode 70, 70A. However, by providing a plurality of index electrodes 70, 70A, the electron beams 5L, 5R are detected. Can be detected independently of each other. In this case, a plurality of capacitors for outputting an index signal are provided, and the index detection signals generated by the respective electron beams are independently processed. By providing a plurality of index electrodes 70 and 70A, the scanning positions of the electron beams 5L and 5R can be detected independently and simultaneously, respectively.
The left and right split screens can be corrected simultaneously.

The above-mentioned index information signal S2
It is possible to arbitrarily set the timing of controlling the image display based on. For example, it is possible to select the operation to be performed at the time of starting the cathode ray tube, to perform the operation intermittently at regular intervals, or to perform the operation at all times. Further, control of image display may be performed alternately on the left and right divided screens. Furthermore, if a so-called feedback loop is configured to reflect the control result of the image display at the time of the next field scan of each electron beam 5L, 5R, the installation position and the direction can be changed during the operation of the cathode ray tube. Even if such is the case, it is possible to automatically correct image distortion and the like due to changes in the external environment such as geomagnetism. Furthermore, even when the scanning screen fluctuates due to the temporal change of each processing circuit, it is possible to automatically absorb the fluctuation and display an appropriate image.
If the operation of each processing circuit is stable and the installation position is unchanged, it is sufficient to perform the correction only at the time of starting the cathode ray tube. As described above, in the present cathode ray tube, the influence of changes in the external environment such as terrestrial magnetism and the aging of each processing circuit on the image display is automatically corrected, and the left and right divided screens are appropriately connected and displayed.

Next, the phase difference between the reference signal _Sref and the index detection signal _Sind , the method of extracting those signals, and the signal output capacitors C10,
The relationship with the formation position of C20 will be described.

First, referring to FIG. 11 and FIG. 12, the reference signal output capacitor C
The structure of the reference signal output capacitor C21 as a comparative example with respect to 20 will be described. As already described with reference to FIGS. 3 and 4, the reference signal output capacitor C20 of the present cathode ray tube is provided with an internal electrode 45 having the same structure as the index signal output capacitor C10 inside the tube. . On the other hand, the reference signal output capacitor C21 of the comparative example is similar to that of FIGS.
As shown in (1), the internal conductive film 22 itself is used as an internal electrode. As shown in FIG. 11, the reference signal output capacitor C21 has the reference signal output external electrode 44 opposed to the internal conductive film 22 with the dielectric portion 46 interposed therebetween.
It has the ability (capacitance) to accumulate charges. An anode terminal 24 (FIG. 6) is provided on the internal conductive film 22.
, The reference signal _Sref using the anode voltage HV is output from the reference signal output capacitor C21.

<Specific Example of Phase Difference> Next, a specific example of the phase difference between the reference signal _Sref and the index detection signal _Sind will be described. FIGS. 13 and 14 show enlarged signal waveforms of the reference signal _Sref and the index detection signal _Sind obtained when the mounting position and the structure of the reference signal output capacitor are variously changed. 13 and 14, the horizontal axis represents time (se
c) is shown. The vertical axis indicates the relative value (au) of the output value of each signal. In FIG. 13, waveform 151
Indicates an index detection signal S _ind and a waveform 152
Indicates a reference signal _Sref . In FIG.
The position indicated by reference numeral 150 is the index detection signal S
The peak position of the waveform 151 of _ind is shown. 14, a waveform 161 indicates the index detection signal S _ind , and waveforms 162 to 163 indicate the reference signal S _ref . In FIG. 14, the position indicated by reference numeral 160 indicates the peak position of the waveform 161 of the index detection signal S _ind .

The signal waveforms of FIGS. 13 and 14 are obtained under the following conditions. As a method of extracting the reference signal _Sref , a method using the reference signal output capacitor C20 having the structure shown in FIG.
This is referred to as “removal method B”. ) And a method using the reference signal output capacitor C21 having the structure shown in FIG. 11 (hereinafter, referred to as “extraction method A”). Further, the extraction position of the reference signal S _ref (the formation position of the reference signal output capacitor) is different from the position where the signal is extracted from a position close to the formation position of the index signal output capacitor C10 and the position where the signal is relatively distant. And the case where the signal was extracted from the. Specifically, as shown in FIG. 6, the index signal output capacitor C10 is formed at a position 20-1 (position) substantially at the center of the upper part of the cathode ray tube, and the reference signal output capacitor is located adjacent to the position. The case of forming at the position 20-2 (position) and the case of forming at the lower position 20-3 (position) remote from the position were examined.

A chassis (circuit board) having a source of the anode voltage HV (mainly a flyback transformer)
Was installed below the cathode ray tube. The anode terminal 24 for supplying the anode voltage HV was provided slightly above the center of the rear part of the cathode ray tube. The screen size of the cathode ray tube used was 36 inches.

FIG. 16 specifically shows the size of the electrodes used when the reference signal _Sref is extracted from the position by the extraction method B. As shown in FIG. 16, in this case, the internal electrode 42 of the index signal output capacitor C10 and the internal electrode 45 of the reference signal output capacitor 20 are each 40 m in length.
m squares were used. The distance between the electrodes is 15 mm, and the internal conductive film 22 of each internal electrode is
The distance from was set to 20 mm. The same applies to the external electrodes 41 and 44. The size of the electrode when the reference signal _Sref is extracted by another position and another extraction method is the same as that shown in FIG. FIG. 17 specifically shows the size of the electrode inside the tube when the extraction method A is applied. Also in this case, the internal electrode 42 of the index signal output capacitor C10 used was a square of 40 mm square.

In FIGS. 13 and 14, the reference signal _Sref is obtained by examining four combinations of the extraction methods A and B and the position. The relationship between each combination and the illustrated signal waveform is as follows. FIG. 15 shows values of the phase difference of the reference signal _Sref with respect to the index detection signal _Sind in the following combinations (i) to (iv). In FIG. 15,-(minus) indicates that the phase is advanced, and + (plus) indicates that the phase is delayed. The unit of the phase difference value is nanosecond.

(I) Position and extraction method B (waveform 15 in FIG. 13)
2). (Ii) Position and extraction method B (waveform 16 in FIG. 14)
2). (Iii) Position and extraction method A (waveform 1 in FIG. 14)
64). (Iv) Position and extraction method A (waveform 1 in FIG. 14)
63).

As can be seen from FIGS. 13 to 15, (i)
In the case of the combination, the phase difference is very small. In the case of the combination of (ii) to (iv), (i)
The phase difference is larger than in the case of (1). FIG.
4, the phase difference from the peak position of the index detection signal S _ind is indicated by reference numerals 162P to 164P.

As can be seen from the above examination results, the reference signal S _ref is extracted from the index detection signal S _ind by substantially the same structure and the same method (extraction method B), and the formation of each signal output capacitor is performed. When the positions are brought closer, the phase difference between the two signals decreases. One reason for this is that using the same signal extraction method,
In addition, it is considered that the capacitance of each signal output capacitor and the capacitance value of the floating capacitor generated in the tube become almost the same when the mounting position of each electrode is made closer. Also, by bringing the signal extraction position closer, an anode voltage H that generates an unnecessary signal waveform (noise) is generated.
The distance from the V supply source (anode terminal 24) to each signal extraction position, the distance from the chassis portion producing the anode voltage HV to each signal extraction position, and the distance from the deflection yoke are almost the same. . In other words, the path and the distance until an unnecessary signal reaches each signal extraction position through the external conductive film 23, the internal conductive film 22 and the air are determined by the reference signal _Sref and the index detection signal _Sind . It will be almost the same. As a result, it is considered that the amount of phase shift that occurs when an unnecessary signal reaches each signal extraction position is reduced. This is the case when the signal extraction positions are distant for the two types of signal extraction methods A and B (waveform 16 in FIG. 14).
2, 163) are almost the same.

As described above, considering only the phase difference, it is understood that it is better to provide each signal output capacitor as close as possible. More precisely, the formation position of each signal output capacitor should be determined not only by taking into account only the phase difference but also by taking into account the location of the noise source and signal characteristics other than the phase difference. Considered good. However, basically, it is considered that each signal output capacitor should be provided as close as possible.

As described above, according to the present embodiment, the reference signal S _ref and the index detection signal S
_{Since ind} is output from a close position in substantially the same manner, the magnitude of the amplitude of each signal can be made substantially the same, and the phase difference between each signal can be reduced. Thereby, the index detection signal S
Removal of unnecessary signal components included in _ind becomes easy,
From the index detection signal S _ind , only the required index information signal S2 can be extracted with high accuracy and a high SN ratio. Further, there is no need to provide a complicated filter circuit or a phase adjusting means such as a delay equalizer, and the circuit configuration of the signal processing system can be simplified.

As described above, according to the present embodiment, the index detection signal S
_{From ind} , signal components required for image correction and the like can be accurately extracted. This makes it possible to perform highly accurate and highly reproducible image correction in an image correction system using the electric index method.

The present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the cathode ray tube capable of color display has been described, but the present invention can be applied to a cathode ray tube which performs monochrome display. Further, in the above-described embodiment, the case where two electron guns are provided and a single screen is formed by joining two scanning screens has been described. However, the present invention provides three or more electron guns. It is also possible to apply the present invention to a configuration in which one screen is formed by combining three or more scanning screens. Further, in the above-described embodiment, one screen is obtained by partially overlapping the divided screens. However, without providing an overlap area, one end is obtained by simply connecting the ends of the divided screens in a line shape. A screen may be obtained. The present invention is not limited to a double electron gun type cathode ray tube, but can be applied to a general cathode ray tube having only a single electron gun.

[0084]

As described above, claims 1 to 3 are described.
According to the cathode ray tube described in any one of the above, the cathode ray tube is formed using a part of the envelope, and is configured to output the detection signal output from the electron beam detecting means to the outside of the envelope. A first capacitor connected to the anode voltage unit and configured to output a reference signal corresponding to the anode voltage to the outside of the envelope; The first capacitor and the second capacitor are formed to have substantially the same structure as that of the first capacitor using a part of the enclosure, and the phase difference between the detection signal and the reference signal is within a desired range. As a result, the phase difference between the electrical detection signal and the reference signal output in response to the incidence of the electron beam can be reduced without using a complicated circuit configuration. it can Thus, there is an effect that, for example, a signal component required for image correction can be accurately extracted from the detection signal.

Further, according to the signal detecting method for a cathode ray tube according to the fourth aspect, the detection signal and the reference signal are made substantially the same using a part of the envelope, and the phase difference between the detection signal and the reference signal is obtained. Is output to the outside of the envelope from a position close enough to be within the desired range, so that the electrical detection output in response to the incidence of the electron beam without employing a complicated circuit configuration The phase difference between the signal and the reference signal can be reduced, and for example, it is possible to accurately extract a signal component required for image correction.

[Brief description of the drawings]

1A and 1B are diagrams schematically illustrating a cathode ray tube according to an embodiment of the present invention, wherein FIG. 1B is a front view showing a scanning direction of an electron beam in the cathode ray tube, and FIG. IA
FIG. 3 is a sectional view taken along line IA.

FIG. 2 is an explanatory diagram showing another example of a scanning direction of an electron beam.

FIG. 3 is a cross-sectional view showing a configuration of an index signal output capacitor and a reference signal output capacitor.

4A and 4B are diagrams illustrating a structure of an electrode portion in each signal output capacitor illustrated in FIG. 3, wherein FIG. 4A illustrates a structure of an external electrode portion, and FIG. 4B illustrates a structure of an internal electrode portion; ing.

FIG. 5 is a structural diagram showing another example of the structure of the electrode portion in each signal output capacitor.

FIG. 6 is a rear view of the cathode ray tube for explaining a formation position of each signal output capacitor.

FIG. 7 is a circuit diagram showing a circuit example for extracting an index information signal.

FIG. 8 is a block diagram showing a configuration of a signal processing circuit in the cathode ray tube shown in FIG.

FIG. 9 is an explanatory diagram showing a structure of an index electrode in the cathode ray tube shown in FIG. 1 and a position detecting operation using the index electrode.

FIG. 10 is an explanatory diagram showing a structure of an index electrode and a position detection operation using the index electrode when performing main scanning in a vertical direction.

11 is a sectional view showing a comparative example of the reference signal output capacitor shown in FIG. 3;

12A and 12B are diagrams illustrating a structure of an electrode portion in each of the signal output capacitors illustrated in FIG. 11, wherein FIG. 12A illustrates a structure of an external electrode portion, and FIG. 12B illustrates a structure of an internal electrode portion; ing.

FIG. 13 is a waveform chart showing the waveform of each signal when the phase difference between the reference signal and the index detection signal is small.

FIG. 14 is a waveform diagram showing the waveform of each signal when the phase difference between the reference signal and the index detection signal is large.

FIG. 15 is an explanatory diagram showing a phase difference between a reference signal and an index detection signal by a specific numerical value for each combination of signal extraction methods.

16 is an explanatory diagram showing numerical values such as the size of each electrode used for extracting the signal waveform shown in FIG.

FIG. 17 is an explanatory diagram showing specific numerical values such as the size of an internal electrode of a signal output capacitor when a take-out method different from FIG. 16 is applied.

FIG. 18 is an explanatory diagram showing an index information signal and an unnecessary signal component included in an output signal from an index electrode.

19 is an enlarged view of an index signal portion shown in FIG.

[Explanation of symbols]

C10: Index signal output capacitor, C20,
C21 ... reference signal output capacitors, OS ... overscan area, S _ind ... index detection signal, S _{r ef} ... reference signal, S2 ... index information signals, S3L,
S3R: modulation signal, S4: correction signal, 5L, 5R: electron beam, 10: panel unit, 11A: fluorescent screen, 11B: tube surface, 13: frame, 20: funnel unit, 21L, 2
1R: deflection yoke, 22: internal conductive film, 23: external conductive film, 30L, 30R: neck portion, 31L, 31R: electron gun, 32L, 32R: convergence yoke, 41: index signal output external electrode, 42: index Internal electrodes for signal output, 43, 46: dielectric portion, 44: external electrodes for reference signal output, 45: internal electrodes for reference signal output, 50: signal extraction circuit, 53: difference circuit, 70, 70A: index electrode, 105: index signal processing circuit; 108: deflection circuit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/68 H04N 5/68 Z 9/16 9/16 9/24 9/24 C

Claims (4)

[Claims] 1. An envelope, an anode voltage section to which an anode voltage is supplied, an electron gun that emits an electron beam for scanning an effective screen area and an overscan area outside the effective screen, Provided in the overscanning area inside the enclosure,
Electron beam detection means for outputting an electrical detection signal in response to the incidence of the electron beam; and a detection signal which is formed using a part of the envelope and is output from the electron beam detection means. A first capacitor configured to output to the outside of the envelope; and a first capacitor connected to the anode voltage unit and configured to output a reference signal corresponding to the anode voltage to outside of the envelope. A second capacitor, wherein the second capacitor is formed to have substantially the same structure as the first capacitor by using a part of the envelope, and the second capacitor has the same structure as the first capacitor. A cathode ray tube, wherein the second capacitor is arranged so close that the phase difference between the detection signal and the reference signal falls within a desired range. 2. The container according to claim 1, wherein the envelope includes a component having a dielectric property, and an inner surface is partially covered with the conductive internal conductive film. A first dielectric portion formed by utilizing a part of the component having the dielectric property, and the internal conductive film on the inner surface of the envelope while being connected to the electron beam detecting means. A first internal electrode attached to a region not provided, and a first external electrode disposed to face the first internal electrode via the first dielectric portion, The second capacitor is connected to a second dielectric portion formed by using a part of the component having the dielectric property and the anode voltage portion, and is provided on the inner surface of the envelope. Attached to the area where the conductive film is not provided 2. The semiconductor device according to claim 1, further comprising a second internal electrode provided and a second external electrode disposed to face the internal electrode via the second dielectric portion. Cathode ray tube. 3. A plurality of electron guns, wherein the effective screen area and the overscan area are scanned by respective electron beams emitted from the plurality of electron guns, and a plurality of divisions formed by the scanning are performed. 2. The cathode ray tube according to claim 1, wherein a single screen is formed and an image is displayed by partially overlapping and connecting the screens. 4. An envelope, an anode voltage section to which an anode voltage is supplied, and an electron gun for emitting an electron beam for scanning an effective screen area and an overscan area outside the effective screen, Outputting an electrical detection signal to the outside of the envelope in response to the incidence of the electron beam that scans the overscan region, and outputting a reference signal corresponding to the anode voltage supplied to the anode voltage unit. A signal detection method in a cathode ray tube configured to output to the outside of an envelope, wherein the detection signal and the reference signal are substantially the same using a part of the envelope, A signal detection method in a cathode ray tube, wherein the signal is output to the outside of the envelope from a position close enough that the phase difference falls within a desired range.