WO2003021627A1

WO2003021627A1 - Cathode-ray tube and display apparatus

Info

Publication number: WO2003021627A1
Application number: PCT/JP2002/007966
Authority: WO
Inventors: Hirokazu Takuma
Original assignee: Sony Corporation
Priority date: 2001-08-31
Filing date: 2002-08-05
Publication date: 2003-03-13
Also published as: JP2003077405A

Abstract

A cathode-ray tube capable of performing dynamic convergence correction without distorting a spot or deteriorating focus. The cathode-ray tube deflects two electron beams (E1, E2) which have passed through a main focus lens. A convergence electrode (10) has an inner electrode plate (11) to which a first voltage is applied and an outer electrode plate (12) which opposes to the inner electrode plate and to which a second voltage lower than the first voltage is applied. The cathode-ray tube includes an electron gun (7) having the convergence electrode (10) and a focus electrode (G4) to which parabolic dynamic focus voltage which has been synchronized with the horizontal deflection cycle and amplitude-modulated by the vertical deflection cycle is applied. The focus electrode (G4) and the outer electrode plate (12) of the convergence electrode (10) are coupled by an electrostatic capacity (C), so as to dynamically change the second voltage applied to the outer electrode plate, thereby performing dynamic convergence correction.

Description

Description cathode ray tube and display device

The present invention relates to a cathode ray tube provided with an electron gun with a compassence electrode, and a display device using the same. Background art

In television receivers and the like, a display device with a larger screen size is demanded in order to provide viewers with a large screen that has a sense of reality and a powerful image. With the current color cathode ray tube, a large display device with a screen size equivalent to a 40-inch has been realized. However, such a large-sized display device weighs more than 100 Kg, which makes it difficult to install it in a general home. Therefore, a rear-type projector device using a cathode ray tube has been used as a device that can easily enjoy a large screen even in ordinary households.

The rear-type projector uses three single-color cathode ray tubes corresponding to red, green, and blue, respectively, and enlarges and projects the image projected on each cathode ray tube on a transmission screen with a lens. I do. As a result, a color image obtained by synthesizing the video corresponding to each color is displayed on the screen, so that the synthesized image (color image) can be viewed through the transmissive screen.

By the way, in the case of such a rear-type projector, the screen size of a single-color cathode ray tube is as small as 7 to 9 inches, and the image projected on this small screen is enlarged and projected on a large screen. It is difficult to obtain high brightness. Therefore, one of the methods to improve brightness Thus, a method has been proposed to increase the number of electron beams in a monochromatic cathode ray tube from one to a plurality.

However, in order to increase the number of electron beams, when each electron beam is scanned on the screen of the cathode ray tube, it is necessary to concentrate the electron beam at one point in all areas on the screen (compensation ence). is there. The reason for this is that if the electron beam does not concentrate on one point on the screen, that is, if the so-called deviation of the convergence occurs, the image will appear blurred at that point. Therefore, as a technology for correcting the deviation of the comparence on the screen, a dynamic convergence correction technology using the following methods (1) to (3) is known.

(1) A method for correcting dynamic compensity by deflecting the deflection magnetic field of the deflection yoke, the horizontal deflection magnetic field into a pincushion shape, and the vertical deflection magnetic field into a barrel shape.

(2) A method of mounting a convergence yoke on a cathode ray tube and supplying a correction signal to the convergence yoke to perform dynamic convergence correction.

(3) A method of performing dynamic Compensation correction by supplying the Compensation voltage modulated by an external transformer to the Compensation Entry of the electron gun using a coaxial cable.

However, the method described in the above (1) has a disadvantage that the spot shape of the electron beam is distorted or the focus is deteriorated in the peripheral portion of the screen due to the distortion of the deflection magnetic field.

Also, in the method described in (2) above, since the electron beam is deflected by the quadrupole magnetic field formed by the compensence yoke, the quadrupole at the periphery of the screen where the correction amount is large is used. The spot shape of the electron beam was distorted and the focus deteriorated due to the effect of the magnetic field. On the other hand, in the method described in (3) above, since the correction voltage is directly applied to the electron gun compass plate, the compensence correction signal is superimposed on a DC voltage of about 95% of the anode voltage. There is a need. As a result, external transformers that achieve this are very expensive because of the need to provide sufficient insulation for high voltages.

The present invention has been made to solve the above problems, and its main purpose is to provide a cathode ray tube capable of performing dynamic convergence correction without causing spot distortion and focus deterioration. It is an object of the present invention to provide a display device using the same. Disclosure of the invention

The cathode ray tube according to the present invention deflects the two electron beams that have passed through the main focus lens, and has an inner electrode plate to which a first voltage is applied, and a first voltage facing the inner electrode plate and having a first voltage. An electron gun having an outer electrode plate to which a lower second voltage is applied, and a parabolic compensence voltage synchronized with the horizontal deflection period and amplitude-modulated with the vertical deflection period. And a voltage applying means for applying a voltage to the outer electrode plate of the comprence electrode. Further, a display device according to the present invention uses the cathode ray tube having the above configuration.

In the cathode ray tube having the above configuration and a display device using the same, when two electron beams passing through the main focus lens are deflected by the comparability electrode, amplitude modulation is performed in synchronization with the horizontal deflection period and in the vertical deflection period. By applying the parabola-shaped compass ence voltage to the outer electrode plate of the comperence electrode, the second voltage applied to the outer electrode plate with respect to the first voltage applied to the inner electrode plate is increased. Voltage fluctuates dynamically. As a result, two electron beams at the compassence electrode Since the deflection amount of the system dynamically changes in accordance with the waveform of the Compurgeence voltage, it is possible to perform dynamic convergence correction using the Compensation electrode. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram showing an overall configuration of a cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a waveform diagram of a dynamic focus voltage.

FIG. 3A to FIG. 3B are diagrams for explaining specific structural examples of the electrostatic coupling.

4A to 4B are diagrams for explaining another example of the structure of the electrostatic coupling. FIG. 5 is a diagram for explaining the deviation of the comparence on the screen. FIG. 6 is a diagram for explaining another application example of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention when applied to a monochromatic cathode ray tube used in, for example, a rear-type projector will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the overall configuration of a cathode ray tube according to an embodiment of the present invention. In FIG. 1, the main body of the cathode ray tube 1 is constituted by a glass bulb composed of a panel part 2, a funnel part 3 and a neck part 4. A fluorescent screen is formed on the inner surface of the panel unit 2 in a predetermined pattern. The funnel section 3 is provided with a ground terminal 5. A high voltage (anode voltage) is applied to the anode terminal 5 from an anode power supply 6 serving as a high voltage power supply. On the other hand, an electron gun 7 is incorporated in the neck 4. The electron gun 7 has two force sources 8 and 9 and a plurality of electrodes G 1, G 2, which control the amount, moving speed, orbit, and the like of the electrons (beams) emitted from these force sources 8 and 9. It comprises G 3, G 4, G 5, and a compassence electrode 10.

Each of the force swords 8 and 9 has a base metal coated or impregnated with an electron-emitting substance, a cylindrical holding member for holding the base metal, and a heater inserted into a cylinder of the holding member. Heat is used to heat the base metal to a predetermined temperature to emit electrons (thermoelectrons). These cathodes 8 and 9 are arranged side by side in the Y axis direction which is the vertical axis direction of the screen of the cathode ray tube 1.

Each of the electrodes G1 to G5 is arranged in series in the central axis direction of the electron gun 7 (the tube axis direction of the cathode ray tube 1), and the first electrode Gl, The second electrode G2, the third electrode G3, the fourth electrode G4, and the fifth electrode G5.

The comprence electrode 10 is arranged at the tip of the electron gun 7 adjacent to the last electrode G5. The compassence electrode 10 has one inner electrode plate 11 and a pair of outer electrode plates 12 arranged outside the inner electrode plate 11 so as to face the inner electrode plate 11. Further, the pair of outer electrode plates 12 are arranged to face each other with the inner electrode plate 11 interposed therebetween.

Here, the third electrode G3, the fourth electrode G4, and the fifth electrode G5 form a main focus lens (electron lens) on the trajectory of the electron beam. In forming this main focus lens, a dynamic focus voltage is applied to the fourth electrode G4 by the focus power supply 13 and the dynamic focus signal generator 14, and the third electrode G3 and the A high voltage supplied from the anode power supply 6 via the anode terminal 5 is applied to the fifth electrode G5.

The dynamic focus voltage is obtained by modulating the focus voltage supplied from the focus power supply 13 with the dynamic focus signal generator 14, and the waveform diagram is shown in FIG. As shown in the figure, the dynamic focus voltage has a parabolic waveform synchronized with the horizontal deflection period (1H), and its amplitude is modulated by the vertical deflection period (IV). Incidentally, Δ Δ in the figure indicates the potential difference in the horizontal deflection cycle, and Δν indicates the potential difference in the vertical deflection cycle.

On the other hand, in the comparison electrode 10, a high voltage (same potential) as that of the third electrode G 3 and the fifth electrode G 5 is applied to the inner electrode plate 11, and a pair of outer electrode plates 1 For 2, a voltage (hereinafter, referred to as a second voltage) slightly lower than the high voltage (hereinafter, referred to as a first voltage) applied to the inner electrode plate 11 is applied.

The second voltage applied to the outer electrode plate 12 is divided using two resistors R 1 and R 2. A variable resistor VR is connected in series to the resistor R2. This variable resistor VR adjusts the voltage applied to the outer electrode plate 12 so that the two electron beams Ε1 and Ε2 emitted from the power sources 8 and 9 are compared at the center of the screen. It is for doing.

Here, the cathode ray tube 1 according to the present embodiment is provided with a voltage applying means for applying the dynamic focus voltage shown in FIG. 2 as a compensating voltage to the outer electrode plate 12 of the convergence electrode 10. It has a configuration. This voltage applying means is configured by coupling the fourth electrode G4 and the outer electrode plate 12 with a capacitance C.

As a specific example of the structure of the electrostatic coupling, as shown in FIGS. 3 to 3, a conductive (metal or the like) having an inner diameter larger than the outer diameter of the fourth electrode G4 is used. A cylindrical body 15 is provided, and the fourth electrode G4 is coaxially inserted into the cylindrical body 15 and arranged. Then, the cylindrical body 15 and the outer electrode plate 12 are electrically connected by a lead or the like. As a result, a capacitance is provided in the gap between the fourth electrode G4 and the cylindrical body 15, so that a state in which the fourth electrode G4 and the outer electrode plate 12 are electrostatically coupled is obtained. Can be Further, a dielectric material (insulator) may be interposed between the fourth electrode G4 and the cylindrical body 15 to have a capacitance.

As another example of the structure of the electrostatic coupling, as shown in FIGS. 4A to 4B, a conductive film 17 is formed on the outer surface of one outer electrode plate 12 via an insulating film 16. This conductive film 17 is electrically connected to the fourth electrode G4. As a result, the insulating film 16 has a capacitance at the portion, so that a state where the fourth electrode G4 and the outer electrode plate 12 are electrostatically coupled can be obtained.

Next, an operation function of the cathode ray tube 1 having the above configuration will be described. First, two electron beams E 1 and E 2, each of which has an emission source of each of the power sources 8 and 9, are a main focus lens formed by a third electrode G 3, a fourth electrode G 4, and a fifth electrode G 5. After crossing at the center of, it spreads outward once and enters the comparison electrode 10. At this time, the electron beam E 1 having the force source 8 as the emission source passes between the outer electrode plate 12 and the inner electrode plate 11 at the bottom of FIG. The emitted electron beam E 2 passes between the other outer electrode plate 12 (upper part in FIG. 1) and the inner electrode plate 11.

As described above, when passing the electron beams E 1 and E 2, the first voltage (high voltage) is applied to the inner electrode plate 11 and the second voltage is applied to the pair of outer electrode plates 12. As a result, the electron beams El and E2 are deflected inward from each other according to the potential difference therebetween. The amount of deflection of the electron beams E 1 and E 2 by the comparison electrode 10 increases as the difference (potential difference) between the first voltage and the second voltage increases. Therefore, by appropriately adjusting the voltage applied to the outer electrode plate 12 with the variable resistor VR, the two electron beams E 1 and E 2 can be made to collage at the center of the screen. However, when the two electron beams E 1 and E 2 are deflected horizontally and vertically by the deflection magnetic field of the deflection yoke (not shown) under the condition that the voltage applied to the outer electrode plate 12 is kept constant, On the screen of the cathode ray tube 1, a deviation of the compensence occurs as shown in FIG. In other words, at the intersection of the X-axis and Y-axis, which is the center of the screen, the two electron beams E 1 and E 2 are concentrated at the-point. The deviation of the purge ence becomes large. As a result, the deviation of the compass ence becomes maximum at the peripheral portion (corner portion) of the screen.

On the other hand, in the configuration in which the fourth electrode G 4 serving as the focus electrode and the outer electrode plate 12 of the convergence electrode 10 are electrostatically coupled, the dynamic focus voltage applied to the fourth electrode G 4 is the same as that of the fourth embodiment. A convergence voltage having the following waveform is applied to the outer electrode plate 12. In such a case, the first voltage applied to the inner electrode plate 11 is a fixed voltage, and the second voltage applied to the outer electrode plate 12 is dynamic according to the waveform diagram shown in FIG. Will fluctuate.

By the way, in the actual circuit operation, the compassence voltage is applied to the outer electrode plate 12 in the form that the dynamic focus voltage is superimposed on the voltage divided by the resistors R 1 and R 2 and the voltage adjusted by the variable resistor VR. However, when deflecting the electron beam, the voltage components due to the resistors R 1 and R 2 and the variable resistor VR are kept constant.

Here, in the waveform diagram shown in FIG. 2, during the horizontal deflection period (1H) in which the electron beams El and E2 are scanned along the X-axis direction of the screen, the voltage level changes from the high voltage side to the low voltage side. And then fluctuates from the low pressure side to the high pressure side. In this case, the voltage level becomes the maximum when beam scanning the X-axis end of the screen. Minimum when scanning the intersection with the Y axis. As a result, the deflection amount (degree of inward) of the electron beams Ε 1 and Ε 2 due to the convergence electrode 10 becomes smaller as the beam scanning position approaches the X-axis end of the screen.

Also, during the vertical deflection period (IV) in which the electron beam El, Ε2 is scanned along the Υ-axis direction of the screen, the voltage level fluctuates from the high voltage side to the low voltage side and then from the low voltage side to the high voltage side. I do. In this case, the voltage level becomes maximum when beam scanning is performed at the Υ-axis end of the screen, and becomes minimum when beam scanning is performed at an intersection with the X-axis. As a result, the deflection amount (degree of inward) of the electron beam E l, Ε 2 by the compassence electrode 10 becomes smaller as the beam scanning position approaches the Υ-axis end.

As described above, the amount of deflection of the two electron beams El, Ε2 at the compensence electrode 10 dynamically changes according to the waveform of the dynamic focus voltage (comparance voltage). Therefore, the two electron beams Ε 1 and Ε 2 passing through the compar- ence electrode 10 move as the beam scanning position moves away from the center of the screen (the intersection of the X axis and the 走 axis). Focus more far away. As a result, dynamic convergence correction is realized, so that the two electronic beams # 1 and # 2 can be concentrated at one point in all areas of the screen.

Further, when the two electron beams E l and Ε 2 pass through the compensence electrode 10, the respective electron beams E l and Ε 2 are deflected without being subjected to the concentration action by the magnetic field, The distortion of the beam spot on the screen can be reduced. As a result, it is possible to simultaneously improve the focus characteristics and correct the dynamic variance.

Furthermore, since the fourth electrode G 4 and the outer electrode plate 12 are electrostatically coupled to each other, a configuration that can apply a compassence voltage to the outer electrode plate 12 is adopted. There is no need to provide a separate external device for dynamic convergence correction. Therefore, it is possible to significantly reduce costs and power consumption.

In the above embodiment, an electron gun of a type in which one electron beam is extracted from one force sword has been described as an example. In addition, a plurality of electron beams can be extracted from one cathode. A so-called multi-beam type electron gun may be used.

Further, in the above-described embodiment, an example in which the invention is applied to a monochromatic cathode ray tube used in a rear-type projector device has been described. However, the present invention is not limited to this. Applicable.

FIG. 6 is a schematic diagram showing an example of application to a trinitron color cathode ray tube. This type of color cathode ray tube is composed of three force sources 21 1, 22, and 23 corresponding to red, green, and blue colors, a plurality of electrodes G 1 to G 5, and a compensating electrode 24. In-line type electron gun 25 is provided. The three electron beams R, G, and B emitted in an in-line arrangement from the electron gun 25 irradiate the phosphor screen 27 through a blind aperture grill 26.

The three electron beams R, G, and B emitting from each of the force sources 21, 22, and 23 are formed by the third electrode G3, the fourth electrode G4, and the fifth electrode G5. After passing through the main focus lens, the light enters the comparison electrode 24. Compensation electrode 24 includes a pair of inner electrode plates 28 arranged opposite to each other, and a pair of outer electrode plates 29 arranged outside each inner electrode plate 28 so as to face each other. Have.

The electron beam R for the green color passes through the space between the inner electrode plate 28 and the outer electrode plate 29 on the lower side in the figure, and the electron beam R for the green color is emitted from the compensence electrode 24 having the above-described configuration. G passes between a pair of inner electrode plates 28, The electron beam B for blue passes between the other inner electrode plate 28 and the outer electrode plate 29 (upper part of the figure). At this time, the fourth electrode G4 and the outer electrode plate 29 are coupled with a capacitance C, whereby the dynamic focus voltage applied to the fourth electrode G4 is converted into a dispersion voltage as the outer electrode plate. By adopting a configuration in which the voltage is applied to 29, the same operation and effect as in the above embodiment can be obtained.

As described above, according to the present invention, there is provided a voltage applying means for applying a parabolic compassence voltage, which is synchronized with the horizontal deflection cycle and amplitude-modulated at the vertical deflection cycle, to the outer electrode plate of the comparence electrode. Thus, the second voltage applied to the outer electrode plate can be dynamically changed so that the two electron beams can be concentrated at one point in each part (the center, the periphery, etc.) on the screen. As a result, it is possible to simultaneously improve the focus characteristics and correct the dynamic convergence.

Claims

The scope of the claims

1. It deflects the two electron beams that have passed through the main focus lens, and an inner electrode plate to which a first voltage is applied, and a second electrode plate facing the inner electrode plate and lower than the first voltage. And an outer electrode plate to which a voltage is applied.

Voltage applying means for applying a parabola-shaped compensence voltage synchronized with a horizontal deflection cycle and amplitude-modulated with a vertical deflection cycle to the outer electrode plate of the compensence electrode;

A cathode ray tube comprising:

2. The electron gun forms the main focus lens and has a focus electrode to which a parabolic dynamic focus voltage synchronized with a horizontal deflection cycle and amplitude-modulated with a vertical deflection cycle is applied, 2. The cathode ray tube according to claim 1, wherein said voltage applying means is constituted by electrostatically coupling said focus electrode and said outer electrode plate of said Compensation electrode.

3. It deflects the two electron beams that have passed through the main focus lens, and an inner electrode plate to which a first voltage is applied, and a second electrode plate facing the inner electrode plate and lower than the first voltage. And an outer electrode plate to which a voltage is applied.

A display device using a cathode ray tube comprising: