JP2002042684A - Color cathode-ray tube ! color picture tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode-ray tube having a flat panel with excellent focusing characteristics and shortened overall length. SOLUTION: This color cathode-ray tube comprises a vacuum envelope having a panel 1 with a screen coated with a phosphor on the inner surface thereof and with a nearly flat outer surface approx. 51 cm in effective diagonal diameter of, a neck 3 having an electron gun 10 therein, and a funnel 3 for connecting the panel to the neck. The electron gun 10 in the neck 3 comprises a cathode, a first electrode, a second electrode, a focusing lens electrode, and a main lens electrode. Where the equivalent radius of curvature of the internal surface of the panel 1 in X-direction is Rix and the equivalent radius of curvature in Y-direction Riy, a distance Lm between the cathode and the screen side end part of the electron on the focusing lens forming electrode side forming the main lens 37<=Lm<=45 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube and, more particularly, to a color cathode ray tube having a panel whose outer surface has an equivalent radius of curvature larger than that of its inner surface, and extending the electrode length of an electron gun without extending the entire length. Color cathode ray tube with improved focus characteristics.

[0002]

2. Description of the Related Art In a color cathode ray tube conventionally used as a picture tube of a television receiver or a monitor tube of a personal computer or the like, the inner and outer surfaces of a panel forming a screen are both curved surfaces.

FIG. 6 is a sectional view schematically illustrating a schematic structure of a conventional color cathode ray tube. In this color cathode ray tube, a glass material is formed by a panel for forming a screen (phosphor screen, also referred to as a screen) by coating a phosphor on an inner surface thereof, a neck 3 containing an electron gun, and a funnel 2 connecting the panel and the neck. It constitutes a vacuum envelope.

The inner and outer surfaces of the panel are both 1.35 × 10
^It has a radius of curvature of about ³ mm, and is provided with a shadow mask, which is a color selection electrode, near the screen formed on the inner surface (not shown). In the figure, Rix indicates an equivalent radius of curvature of the panel inner surface in the X direction, and Riy indicates an equivalent radius of curvature of the panel inner surface in the Y direction.

An electron gun 10 for emitting three electron beams toward the screen is accommodated in the neck 3.
In the transition region between the funnel 2 and the neck 3 of the vacuum envelope,
The three electron beams emitted from the electron gun are applied to the screen X
A deflection yoke 11 is mounted for deflecting in a direction (generally a horizontal direction) and a Y direction (generally a vertical direction) to reproduce a two-dimensional image on a screen. In addition, ZZ indicates the tube axis direction.

The outer shape of the panel 1 has a long axis in the X direction,
It has a substantially rectangular shape having a short axis in the direction, and the display area AR is formed within its maximum outer size. The electron beam emitted from the electron gun 10 is deflected from the center (deflection center) 12 of the deflection magnetic field formed by the deflection yoke at an effective maximum deflection angle θ,
The above-described display area AR is formed.

[0007] The focus characteristic of the electron beam that collides with the screen affects the quality of the reproduced image. The electron gun 10 includes a cathode and an electron beam generator including a first electrode and a second electrode arranged in order from the cathode to the screen.
And a focusing lens forming electrode and a main lens forming electrode sequentially arranged on the screen side of the electron beam generating section.

The parameters for determining the focus characteristics include the electrode length Lm of the electron gun, the distance Lc between the electron gun and the screen, the distance between the deflection center and the maximum outer shape point of the effective display area (Lw · cos θ), There is a distance Ld between the cathode side electrode constituting the main lens of the electron gun 10 and the deflection center 12.

It is known that the above-mentioned distance Ld needs to be separated by a certain distance or more to such an extent that the electron gun is not affected by the deflecting magnetic field. The longer the electrode length Lm of the electron gun is, the more the focus characteristic becomes. It is also known to be good.

[0010] In recent years, with the trend toward larger screens, color cathode ray tubes of flat face type or flat panel type, in which the outer surface of the panel is substantially flat, have been widely used in color cathode ray tubes.

In such a color cathode ray tube having a flat panel outer surface, further improvement in focus characteristics is required by flattening the panel outer surface.

Japanese Patent Application Laid-Open No. H10-64451 can disclose a conventional technique relating to a flat panel type (hereinafter, also referred to as a flat panel type) color cathode ray tube of this type.

[0013]

In the flat panel type color cathode ray tube described above, an improvement in focus characteristics is required as the inner surface of the panel is flattened. Due to the increase in the radius of curvature of the inner surface of the panel, the angle of incidence of the electron beam on the panel at the periphery of the screen increases, and the focus characteristics deteriorate.

Further, in a device such as a television receiver or an information terminal such as a personal computer monitor, in addition to a demand for increasing the screen size (screen size), a reduction in the depth size is required. In particular, a cathode ray tube having a maximum electron beam deflection angle of 90 degrees has a long funnel portion. Therefore, it is difficult to reduce the depth size of the cathode ray tube. Also,
It is difficult to reduce the distance between the inner surface of the panel and the screen-side end surface of the focusing electrode.

If the electrode length of the electron gun is kept large, the overall length of the color cathode ray tube becomes large, and the demand for a reduction in the depth size cannot be satisfied.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a flat panel type color cathode ray tube having good focus characteristics and a shortened overall length.

[0017]

As described above, the relationship between the electrode length Lm of the electron gun and the focus characteristics requires that the electrode length Lm be increased as described above, and that the electron gun and the screen tube distance Lc It is also known that the smaller the Lw / cos θ, the better the focus characteristics.

When a flat color cathode ray tube is constructed with the same deflection angle θ as that of a conventional color cathode ray tube having the same effective screen size, there is no change in Lw / cos θ.

The distance Lc between the electron gun and the screen is determined by calculating the equivalent radii of curvature in the X and Y directions on the inner surface of the panel as Rix and Ri.
When y is represented by the following equation.

Lc = Lw + Ld + Rix−√ ((Rix−Riy + √ (R
iy ² −150 ² )) ² −200 ² ) The present invention reduces the distance Lc between the electron gun and the screen tube by increasing the equivalent radii of curvature Rix and Riy of the inner surface of the panel in the X and Y directions. Is the electrode length Lm of the electron gun.
Is an extension of

The operation and effect of the configuration of the present invention described above will be described in detail in the embodiments, but the present invention is not limited thereto, and departs from the technical idea of the present invention. Needless to say, various modifications are possible.

[0022]

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

FIG. 1 is a sectional view schematically illustrating a structural example of a flat panel type color cathode ray tube according to the present invention. This color cathode ray tube has a phosphor layer on the inner surface of a panel 1 to form a screen, a neck 3 accommodating an electron gun, and a funnel 2 connecting the panel and the neck to form a vacuum envelope. .

The horizontal direction of the panel 1 forming the screen is the X direction, and the vertical direction orthogonal to the main scanning direction is the Y direction.
Direction, and a tube axis orthogonal to the XY plane is indicated by Z.

This color cathode ray tube has a screen in which a phosphor is applied to the inner surface of a substantially rectangular panel 1 having a major axis in the X direction and a minor axis in the Y direction. Neck 3
Accommodates an electron gun for emitting three electron beams toward the screen direction, and connects a panel 1 and a neck 3 with a funnel 2 to form a vacuum envelope.

This color cathode ray tube is a nominal 21 inch color cathode ray tube having a substantially flat outer surface having an effective diagonal diameter of the panel 1 of about 51 cm as viewed from the observation side.

As will be described later, the electron gun accommodated in the neck 3 includes an electron beam generating section including a cathode and a first electrode and a second electrode arranged in order from the cathode to the screen, and the screen of the electron beam generating section. It has a focusing electrode and a main lens electrode arranged in order on the side.

In FIG. 1, Lm is the distance between the cathode and the electrode on the focusing electrode side constituting the main lens electrode (referred to here as the electrode length of the electron gun), and 12 is the center of deflection. Lw is the distance between the deflection center 12 and the electrode on the focusing electrode side constituting the main lens electrode, and Lw is the distance between the vertical line lowered from the outer edge of the effective area AR of the screen to the tube axis and the deflection center 12, Ld Is the distance from the deflection center 12 to the focusing electrode side electrode constituting the main lens electrode, Lc
Indicates the distance between the inner surface of the panel on the tube axis ZZ and the electrode on the focusing electrode side constituting the main lens electrode. And L
t is the total length of the color cathode ray tube along the line ZZ.

Rix indicates an equivalent radius of curvature of the inner surface of the panel 1 in the X direction, and Riy indicates an equivalent radius of curvature of the inner surface in the X direction. Here, the definition of the equivalent radius of curvature is shown in FIG.
This will be described with reference to FIG.

FIG. 2 is a partial sectional view for explaining the definition of the equivalent radius of curvature of the inner surface of the panel. When the inner surface of the curved panel has an aspherical shape, the radius of curvature varies depending on an arbitrary position on the inner surface of the panel. Therefore, the curvature of the inner surface of the panel can be defined as an equivalent radius of curvature Rix (mm) as follows.

Rix = (Zd ² + Dd ² ) / 2Zd where Dd is the distance (m) in the direction perpendicular to the tube axis from the tube axis ZZ on the inner surface of the panel to the end of the effective area of the screen.
m) and Zd are from the center of the panel inner surface at the end of the effective area of the screen (intersection with the tube axis ZZ) to the tube axis ZZ.
The amount of drop in the direction (mm).

The same applies to the case where the X direction is replaced with the Y direction or the diagonal direction, and the same applies when the inner surface of the panel is replaced with the outer surface of the panel. Alternatively, the same definition can be made by replacing the inner surface of the panel with a shadow mask (press mask) which is curved in accordance with a curved surface.

Depending on the screen size of the cathode ray tube,
Even if the radius of curvature of the panel outer surface is the same, the flat feeling is different. Therefore, as an evaluation of the flat feeling, the outer surface radius of curvature Ro (m) is standardized regardless of the screen size.
m) and the inner surface radius of curvature Ri (mm) are defined as follows.

Ro = 42.5V + 45.0 Ri = 40.0V + 40.0 where V is the effective diameter (inch) in the diagonal direction of the screen.
Then, the degree of flatness of the panel can be expressed by a multiple of the outer surface radius of curvature Ro or the inner surface radius of curvature Ri of the standardized panel. The “inch” representing the effective diameter mentioned above is a term commonly used to represent the screen size of a cathode ray tube, and is generally a term such as “XX inch type cathode ray tube”. Is used as such.

FIG. 3 is a side view, partially in section, showing a configuration example of an electron gun housed in the neck of the color cathode ray tube shown in FIG. 1 for explaining the first embodiment of the present invention. In the figure, K
Is a cathode, 20 is a first electrode, 21 is a second electrode,
The cathode K, the first electrode 20 and the second electrode 21 constitute a so-called electron beam generator.

Then, various electrodes (third electrode 22, fourth electrode 23, fifth electrode 24 and sixth electrode 25 are sequentially arranged in order to form a focusing lens and a main lens in the screen direction of the electron beam generator. The sixth electrode 25 is also called an anode electrode, 26 is a shield cup, and 27 is a beading glass for fixing and holding each electrode at a predetermined order and at a predetermined interval.

The electron gun according to the present embodiment has the third electrode 22 and the fourth electrode
A focusing lens is constituted by the electrode 23 and the fifth electrode 24 composed of the 5-1 electrode 24-1 and the 5-2 electrode 24-2 divided into two. Then, a main lens is formed at an opposing portion between the 5-2 electrode 24-2 and the sixth electrode 25.

The electrode length Lm of the electron gun in this embodiment is
The sixth electrode 25 of the 5-2 electrode 24-2 from the cathode 20
It is the distance between the side end surface.

On the inner surface of the panel 1 of the color cathode ray tube shown in FIG. 1, when the equivalent radius of curvature in the X direction is Rix and the equivalent radius of curvature in the Y direction is Riy, the focusing forming the cathode K and the main lens is performed. Distance between the electrode-side electrode 5-2 and the end face of the electrode 24-2 on the sixth electrode 25 side (electrode length)
Let Lm be 37 ≦ Lm ≦ 37 + 23.4− (Rix−√ ((Rix−Riy + √
(Riy ² −150 ² )) ² −200 ² )).

It is to be noted that the conventional amount of depression on the inner surface of the panel (=
Lc-Lw-Ld) is 23.4 mm. The present invention
Specifically, the equivalent radius of curvature Rix in the X direction of the inner surface of the panel
Is 1990 mm and the equivalent radius of curvature Riy in the Y direction is 187
0 mm. The electrode length Lm was set in a range of 37 ≦ Lm ≦ 44.3.

The equivalent radius of curvature of the panel inner surface is given by Rix
By setting Riy, it is possible to reduce the difference in panel thickness between the peripheral portion in the X direction and the peripheral portion in the Y direction. As a result, an image with less distortion can be displayed. Since this panel has a large radius of curvature of the inner surface in the X direction where the deflection angle is large, by implementing the present invention, a great effect of improving the focus characteristics around the panel can be obtained.

The flat panel type color cathode ray tube has both an equivalent radius of curvature Rix in the X direction and an equivalent radius of curvature Riy in the Y direction larger than those of the conventional curved panel type color cathode ray tube. Therefore, in the flat panel type color cathode ray tube, it is understood that the distance Lc between the inner surface of the panel on the tube axis ZZ and the electrode on the focusing electrode side constituting the main lens electrode becomes relatively small.

In a range where the distance Lc is reduced,
The electrode length Lm of the electron gun can be increased without increasing the length Lt in the tube axis direction.

In the case of a monitor color cathode ray tube having a diagonal size of 51 cm of the panel 1 provided with the shadow mask, the electrode length Lm of the electron gun is indispensable for Lm> 35 mm in order to obtain required focus characteristics. It is known that there is.

Generally, a set maker requests a color cathode ray tube having a length corresponding to the size of the monitor set. At present, Lm <
37 mm. On the other hand, according to the present embodiment, it is possible to extend the electron gun electrode length Lm to Lm <44.3 mm.

According to the present invention, the maximum deflection angle of the electron beam is 90.
In the case of a 51 cm-type cathode ray tube, it is possible to improve the focus characteristics and suppress the total length in the tube axis direction to 447 mm. As a result, it is possible to provide a flat panel type color cathode ray tube having good focus characteristics and a reduced overall length.

Further, since the maximum deflection angle of the electron beam is 90 degrees in the cathode ray tube of this embodiment, the power consumption of the deflection yoke is smaller than that of the cathode ray tube having the maximum deflection angle of 100 degrees. Further, the effective screen size is the same as that of the conventional cathode ray tube, the deflection angle θ is the same as that of the conventional cathode ray tube, and the electrode length of the electron gun is longer than that of the conventional electron gun.

FIG. 4 is a side view, partially in section, showing a configuration example of an electron gun housed in the neck of the color cathode ray tube shown in FIG. 1 for explaining a second embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 3 correspond to the same functional portions, 28 denotes an intermediate electrode, and 29 denotes a built-in resistance element.

In the electron gun of this embodiment, similarly to the electron gun of FIG. 3, the cathode K, the first electrode 20 and the second electrode 21 constitute a so-called electron beam generator. Then, various electrodes (third electrode 22, fourth electrode 22) for forming a converging lens and a main lens in the screen direction of the electron beam generating section.
An electrode 23 and a fifth electrode 24 serving as an anode electrode are sequentially arranged, and an intermediate electrode 28 is arranged before the sixth electrode 25 (between the fifth electrode 24 and the sixth electrode 25).

A built-in resistor element 29 is mounted on a beading glass 27 for fixing and holding each electrode at a predetermined order and at a predetermined interval. 28.

The electrode length Lm of the electron gun in this embodiment is
This is the distance between the cathode 20 and the end face of the fifth electrode 24 on the side of the intermediate electrode 28.

According to this embodiment, as in the embodiment shown in FIG. 3, the electrode length Lm of the electron gun can be extended to Lm <44 mm. As a result, when a monitor color cathode ray tube having a panel 1 with a diagonal size of 51 cm is made into a flat panel, the electron gun electrode length Lm can be extended up to 40 mm, the focus characteristics are improved, and the tube becomes the same as the conventional one. The total length in the axial direction can be suppressed to 447 mm. As a result, it is possible to provide a flat panel type color cathode ray tube having good focus characteristics and a reduced overall length.

FIG. 5 is a schematic sectional view for explaining the overall structure of a color cathode ray tube according to the present invention. This color cathode ray tube is a flat panel type color cathode ray tube in which the equivalent radius of curvature of the outer surface 1a of the panel 1 is larger than that of the inner surface 1b.

A phosphor 4 of three colors is applied to the inner surface 1b of the panel 1 to form a screen. A shadow mask structure 50 is provided near the screen 4. The shadow mask structure 50 is, for example, 1.1 m
A shadow mask 6 formed by press-forming a 0.13 mm-thick invar material is welded to a m-thick iron-based metal mask frame 6, and a suspension mechanism 7 having a spring material is attached to a side surface of the mask frame 6. This is engaged with a stud pin 8 buried in the inner wall of the mask 1 and mounted at a predetermined position.

The panel 1 is bonded to a large-diameter opening of a funnel 2 having a funnel shape, and the small-diameter side of the funnel 2 is connected to a neck 3. An electron gun 10 for emitting three electron beams B is housed inside the neck 3. The electron gun 10 is one of those described with reference to FIG. 3 or FIG.

An external magnetic device 12 for color purity correction and the like is provided around the neck 3. A deflection yoke 11 is provided in a transition region between the funnel 2 and the neck 3, deflects the electron beam B in the X direction and the Y direction, and reproduces a two-dimensional image on the screen 4. A magnetic shield 9 for shielding the electron beam B from external magnetism such as terrestrial magnetism is fixed to the neck side of the mask frame 6.

According to the embodiment of the present invention, it is possible to realize a flat panel type color cathode ray tube having a good flat feeling and an improved focus characteristic.

[0058]

As described above, according to the present invention,
It is possible to provide a color cathode ray tube having a panel in which the equivalent radius of curvature of the outer surface of the panel is larger than that of the inner surface, and extending the electrode length of the electron gun without increasing the overall length to improve the focus characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically illustrating a structural example of a flat panel type color cathode ray tube according to the present invention.

FIG. 2 is a partial cross-sectional view for explaining the definition of an equivalent radius of curvature of a panel inner surface.

FIG. 3 is a side view, partially in section, showing a configuration example of an electron gun accommodated in the neck of the color cathode ray tube shown in FIG. 1 for explaining the first embodiment of the present invention.

FIG. 4 is a side view, partially in section, showing a configuration example of an electron gun accommodated in the neck of the color cathode ray tube shown in FIG. 1 for explaining a second embodiment of the present invention.

FIG. 5 is a schematic sectional view illustrating the overall configuration of a color cathode ray tube according to the present invention.

FIG. 6 is a cross-sectional view schematically illustrating a schematic structure of a conventional color cathode ray tube.

[Explanation of symbols]

1 ··· Panel, 2 ··· Funnel, 3 ···
Neck, 4. Screen (screen, phosphor screen), 5.
... shadow mask, 50 ... shadow mask structure, 6 ... mask frame, 7 ... suspension mechanism,
8 stud pins, 9 magnetic shields, 1
0 ... electron gun, 11 ... deflection yoke, 12 ...
..Magnetic device, Lm ........ electrode length of electron gun, Lt ..
..The total length of the color cathode ray tube.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomoki Nakamura 3300 Hayano, Mobara-shi, Chiba Prefecture Within Hitachi, Ltd. Display Group (72) Inventor Shinichi Kato 3300, Hayano, Mobara-shi, Chiba Prefecture F within Hitachi, Ltd. Display Group Terms (reference) 5C032 AA02 BB05 5C041 AA03 AC38 AC39 AD02 AE01

Claims (3)

[Claims] 1. A color cathode ray tube comprising a vacuum envelope formed by a panel having a phosphor screen formed on an inner surface thereof, a neck accommodating an electron gun, and a funnel connecting the panel and the neck. Has a substantially rectangular screen having a major axis in the X direction and a minor axis in the Y direction. The screen has an effective diagonal diameter of about 51 cm. The electron gun accommodated in the neck is separated from the cathode and the cathode by the screen. An electron beam generating section composed of a first electrode and a second electrode sequentially arranged on the side, a focusing electrode and an anode electrode sequentially arranged on the screen side of the electron beam generating section, and the equivalent of the inner surface of the panel in the X direction. When the radius of curvature is Rix and the equivalent radius of curvature in the Y direction is Riy, the distance Lm between the cathode and the screen-side end of the focusing electrode constituting the main lens is: 37 ≦ Lm ≦ 37 + 23.4− (Rix−√ ((Rix−Riy + √ (Riy ² −
150 ² )) ² −200 ² ) A color cathode ray tube characterized by the following. 2. The color cathode ray tube according to claim 1, wherein both the X and Y equivalent radii of curvature of the outer surface of the panel are 1 × 10 ⁴ mm or more. 3. An equivalent radius of curvature of the outer surface of the panel in the X direction and Y direction is 1 × 10 ⁴ mm or more, and an equivalent radius of curvature Rix and Riy of the inner surface of the panel in the X direction and Y direction are R.
2. The color cathode ray tube according to claim 1, wherein ix≥Ry.