JPH1064447A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the unevenness in color due to the generation of distortions by the thermal expansion of electrode by forming a control electrode of a bottom surface part, which is made of a metallic material with a small coefficient of thermal expansion, and a cup part which is made of a metallic material with a large coefficient of thermal expansion. SOLUTION: A bottom surface part 31a made of the metallic material with a small coefficient of thermal expansion (42%Ni-Fe) and a cup part 31 made of the metallic material with a large coefficient of thermal expansion (49%Ni-Fe) are bonded so as to obtain a nearly elliptical or rectangular cup- shaped control electrode 31 having a longitudinal direction in the in-line direction. Three negative electrodes K, in which a heater 21 is housed, are arranged inside of this control electrode 31 in the in-line direction, and fixed integrally with an embedded fixed member 24 for fixing by a heat dam 22 through an insulating body 23.

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 structure in which color unevenness caused by distortion of electrodes constituting an in-line type electron gun due to thermal expansion is reduced. .

[0002]

2. Description of the Related Art A color cathode ray tube is frequently used as a display device of a monitor (monitor terminal) for an information terminal of an information device represented by a television receiver or a personal computer.

FIG. 3 is a cross-sectional view illustrating an example of the structure of a color cathode ray tube to which the present invention is applied.
Is a screen, 2 is a neck, 3 is a funnel, 4 is a phosphor screen, 5 is a shadow mask, 6 is a mask frame, 7
Is a magnetic shield, 8 is a shadow mask suspension mechanism, 9 is an in-line type electron gun, 10 is a deflection yoke, 11 is an inner conductive layer, 12 is an outer conductive layer, 13 is a contact spring for supplying an anode voltage to the electron gun, 14 is a getter, 1
5 is a stem for supplying a video signal and other various voltages to the electron gun, 16 is an anode terminal, 17 is a tension band, and 18 is a correction magnet device.

In this type of color cathode ray tube, a vacuum envelope is formed by a panel section 1 and a neck section 2 and a funnel section 3 connecting the panel section 1 and the neck section 2, and the panel section 1 and the funnel section are formed. 3 is a tension band 17
Be tightened.

On the inner surface of the panel portion 1, there is formed a phosphor screen 4 in which phosphors of three colors of red, green and blue are applied in a stripe or dot form, and a screen 1a is formed on the panel surface.
Is configured.

A so-called in-line type electron gun 9 for emitting three electron beams in-line is provided inside the neck portion 2.
And a shadow mask 5 which is a color selection electrode having a large number of apertures or a grid in the vicinity of the fluorescent screen 4 inside the panel section 1 is provided.

B denotes an electron beam, and a deflection yoke 10 is provided in a transition region between the funnel 3 and the neck 2.

The electron gun 9 is supplied with an anode voltage from a contact spring 13 through an internal conductive layer 11 from an anode terminal 16 formed in a funnel portion through an internal conductive layer 11, and three electron beams B emitted in-line from the electron gun 9. Is the deflection yoke 1
The screen 1a is deflected in two directions, horizontal and vertical, by a vertical deflection magnetic field and a horizontal deflection magnetic field generated at 0, and receives a color selection by a shadow mask 5 and strikes each phosphor forming the phosphor screen 4. To form a color image.

The correction magnet device 18 mounted around the neck 2 is adjusted so that the three electron beams land at one point on the screen.

FIG. 4 is a partially cutaway side view for explaining an example of the in-line electron gun used in the color cathode ray tube shown in FIG. 3, wherein K is a cathode and 31 is a control electrode.
A grid electrode 32, a second grid electrode 33, which is an acceleration electrode;
Reference numerals 34 and 35 denote third, fourth and fifth grid electrodes which are pre-focus electrodes, reference numeral 36 denotes sixth and seventh grid electrodes which are focus electrodes, and reference numeral 37 denotes a third lens which forms a main lens together with the focus electrode 36. A 7 grid electrode (anode electrode), 38 is a shield cup, and 39 is an insulating support rod made of multi-form glass.

In FIG. 1, a first grid electrode 31 serving as a control electrode is cup-shaped, and a second grid electrode 32, a third grid electrode 33, a fourth grid electrode 34 and a fifth grid electrode 35 serving as acceleration electrodes are formed as a single plate. Alternatively, the sixth and seventh grid electrodes 36 and the seventh grid electrode 37 are formed in a cup shape, and each electrode is fixed by a pair of insulating support rods 39 in a predetermined order and at intervals. Then, the cathode K and the control electrode 31
The acceleration electrode 32 constitutes a so-called triode.

FIG. 5 is a sectional view of the in-line electron gun 3 shown in FIG.
It is a principal part sectional view explaining the structure of a pole part, 20 is a cathode sleeve, 21 is a heater, 22 is a heat dam, 23
Is an insulating material, 24 is an embedded fixing member, 25 is an embedded portion welded to the side wall of the control electrode 31, and the same reference numerals as those in FIG. 4 correspond to the same portions.

FIG. 1 is a view as viewed from the in-line direction. A heater 21 is housed in three cathodes K arranged in the in-line direction, and embedded and fixed by a heat dam 22 via an insulator 23 such as ceramics. It is integrated with the member 24 and fixed inside the control electrode 31 by welding. In the figure, x marks indicate welding points.

The control electrode 31 has a substantially elliptical or rectangular oblong cup shape having a long axis in the in-line direction, and an electron beam passage hole is formed at a position corresponding to each cathode K on the bottom surface facing the acceleration electrode 32. Have been.

The accelerating electrode 32 has a plate shape, and an electron beam passage hole is formed at a position corresponding to the electron beam passage hole of the control electrode 31.

In this triode, a change in the gap LG in the direction of the tube axis (Z axis) of the control electrode 31 and the end face of the cathode sleeve forming the cathode K greatly affects the operating current value. That is, while a predetermined current value is set while maintaining a predetermined gap LG in a state where the temperature of each electrode is stable, a so-called transient when the current flowing through the heater 21 is once turned off and then turned on again In this state, the gap LG changes with time, and the operating current changes accordingly. In this case, generally, the smaller the gap LG, the larger the current value, and the smaller the gap LG, the smaller the current value.

The prior art relating to this type of color cathode ray tube is disclosed in JP-A-59-2156.
40.

[0018]

In the above prior art, the cup-shaped control electrode 31 thermally expands during operation due to heat radiation from the cathode K.

FIG. 6 is a cross-sectional view of a main part in an in-line direction for explaining a deviation caused by thermal expansion in a conventional control electrode.

In the same manner, during operation of the cathode ray tube, the control electrode 31 expands due to heat radiation from the cathode K, and the control electrode 31 has a ΔΔ in the Z-axis direction.
It extends by LG, and moves in the in-line direction by ΔS at the center of each side beam passage hole. Here, the S dimension of the cathode K also changes, but since the insulating material 23 is usually made of a low expansion material such as ceramics or hermetic glass, the change is small and can be ignored.

The change in ΔS affects the beam trajectory. If the temperature of the control electrode 31 is saturated for 30 minutes, running for 30 minutes and the electrode temperature of the control electrode 31 is saturated, then three electron beams are applied to one point of the fluorescent screen 4 by the correction magnet device 18 of FIG. Correct to concentrate on

However, since ΔS is almost 0 immediately after the operation is stopped and the operation is started again, the side beam follows a beam trajectory different from that during the operation. After the operation is started, a convergence deviation occurs until the electrode temperature of the control electrode 31 becomes stable (5 to 10 minutes, depending on the design structure, but slightly).

Conventionally, as a countermeasure, the material of the control electrode 31 is changed to a low thermal expansion material. For example, by changing 49% Ni-Fe to 42% Ni-Fe, the convergence deviation due to an increase in the electrode temperature of the control electrode 31 is reduced, and is at a level acceptable in practical use (42% Ni-Fe). Since Fe has a smaller coefficient of thermal expansion than 49% Ni-Fe, the change in ΔS due to a rise in temperature is small, and as a result, the convergence deviation is small.) However, as a side effect thereof, the rise of the beam current immediately after the start of the operation is delayed.

FIG. 7 is an explanatory diagram of the operation time versus current characteristics depending on the difference in the material of the control electrode. The operation time (min) is plotted on the horizontal axis.
And the vertical axis shows the beam current (relative value).

In the figure, a is the characteristic of the control electrode of the specification using 49% Ni-Fe material, and b is the characteristic of the control electrode of the specification using 42% Ni-Fe material.

As can be seen from the figure, the electron gun using the control electrode of the specification a rises to a stable current state in about 1 minute after the start of operation, whereas the electron gun using the control voltage of the specification b has 5 current. A stable current state will not be achieved unless it takes ~ 7 minutes.

The reason for this can be clearly understood from the change in ΔLG with respect to the elapsed time, which most affects the rising characteristic of the beam current due to the difference in the material of the control electrode.

FIG. 8 is an explanatory diagram of the operation time versus ΔLG change characteristic due to the difference in the material of the control electrode. The horizontal axis indicates the operation time (minutes), and the vertical axis indicates ΔLG (μm).

In the figure, a is the characteristic of the control electrode using 49% Ni-Fe as the material, and b is the characteristic of the control electrode using 42% Ni-Fe as the material. Note that ΔLG at the time of stability is set to zero (ΔLG = 0).

As shown in the figure, when the control electrode 31 is made of the thermal expansion material a, the elongation ΔLG in the Z-axis direction at the time of temperature rise is large, so that it is necessary to set ΔLG to a certain specified value when the temperature is stabilized. The initial setting ΔLG may be narrow, but in the case of the low thermal expansion material b, the elongation ΔL in the Z-axis direction when the temperature rises
Since G is small, it is necessary to widen the initial setting ΔLG in order to set ΔLG to a certain specified value when the temperature is stable. As a result, ΔLG does not become very narrow after the start of the operation, and it takes 5 to 7 minutes to reach the minimum gap.

As described above, the conventional technique has a problem that the convergence deviation after the start of the operation and the rising characteristic of the beam current are not compatible.

It is an object of the present invention to provide a color cathode ray tube having an electron gun capable of displaying a high quality image by solving the above-mentioned problems of the prior art.

[0033]

In order to achieve the above object, according to the present invention, a bottom portion and a side portion (cup portion) of a cup-shaped control electrode (first grid electrode) are made of different metals. The bottom portion is made of a low thermal expansion material to reduce the change in ΔS due to the thermal expansion of the bottom portion of the control electrode due to the radiant heat from the cathode, to suppress the convergence deviation, and to make the cup portion a material for the bottom portion. By using a material having a relatively high coefficient of thermal expansion as compared with the above, the configuration was such that the rising characteristics of the beam current were satisfied.

That is, according to the first aspect of the present invention, there are provided three cathodes for emitting three electron beams arranged in-line, a long axis in the in-line direction, and the respective cathodes on the bottom surface. A rectangular cup-shaped control electrode having three opposing electron beam passage holes, and an embedded fixing member for integrating the three cathodes via an insulator and fixing the control electrode inside the control electrode; In a color cathode ray tube equipped with an in-line type electron gun having at least an accelerating electrode, a focusing electrode, and an anode electrode which are arranged and fixed at predetermined intervals in the tube axis direction from the control electrode, the control electrode has a small thermal expansion coefficient. And a cup portion made of a metal material having a large thermal expansion coefficient.

With this configuration, the convergence deviation after the start of the operation and the rising characteristics of the beam current are improved, and a high-quality image display can be obtained.

According to a second aspect of the present invention, in the first aspect of the present invention, a side wall surface substantially parallel to a short axis of the cup portion adjacent to the bottom surface portion of the control electrode is substantially parallel to a long axis. It is characterized by having a slit partially cut in the parallel side wall surface.

With this configuration, the in-line direction of the bottom portion is not accelerated at the cup portion, and the displacement due to the thermal expansion of the cup portion is prevented from affecting the bottom portion. The rising characteristic of the beam current is improved, and a high-quality image display can be obtained.

According to a third aspect of the present invention, in the first or second aspect, the metal material forming the bottom portion is 42% Ni—Fe and the metal forming the cup portion is 42% Ni—Fe. The material is 49% Ni-Fe.

The thermal expansion coefficient of the above 42% Ni—Fe is 50 ×
Since the thermal expansion coefficients of 10 ⁻⁷ and 49% Ni—Fe are 80 × 10 ⁻⁷ , the change in ΔS due to the thermal expansion of the bottom surface is reduced, the convergence deviation is suppressed, and the beam current is reduced. The rising characteristics are satisfied.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to examples.

FIG. 1 shows a first embodiment of a color cathode ray tube according to the present invention.
It is explanatory drawing of the structure of the control electrode and cathode part which comprise the in-line type electron gun used for an Example, (a) is a partial sectional view, (b) is a whole perspective view, 20 is a cathode sleeve, 21 Is a heater, 22 is a heat dam, 23 is an insulating material, 24 is an embedded fixing member, 31 is a control electrode, 31a is a bottom portion, 31b is a cup portion, 31aR, 31aG, 31
aB is an electron beam passage hole, and 25 is an embedded portion.

In the figure, a control electrode 31 is formed by joining a divided bottom portion 31a and a cup portion 31b, and the bottom portion 31a is made of a 42% Ni-Fe material having a relatively low coefficient of thermal expansion.
The cup portion 31b has a relatively high coefficient of thermal expansion of 49% Ni-
It is made of Fe material.

FIG. 5A is a view as seen from the in-line direction. As shown in FIG. 6, three cathodes K arranged in the in-line direction accommodate heaters 21 respectively. Is integrated with the embedded fixing member 24 via the insulator 23 and fixed by welding to the inside of the control electrode 31.

The control electrode 31 has a substantially elliptical or long rectangular cup shape having a long axis in the in-line direction, and an electron beam passage hole is formed at a position corresponding to each cathode K on the bottom surface facing the acceleration electrode 32. Have been.

In this configuration, the bottom surface 31a of the control electrode 31 where the electron beam passage holes 31aR, 31aG, 31aB are formed is made of a 42% Ni--Fe material having a relatively low coefficient of thermal expansion. 21 even when heated by the radiant heat of the heating of the inline direction.
(See FIG. 6) is suppressed, and the convergence deviation is significantly reduced.

On the other hand, since the cup portion 31b is made of a 49% Ni-Fe material having a relatively high coefficient of thermal expansion as in the conventional case, all the deviations ΔLG in the Z-axis direction are made of 49% Ni-Fe material. This is the same as the conventional control electrode, and there is no deterioration in the rising characteristic of the beam current.

As described above, according to the present embodiment, both the reduction of the convergence deviation and the rising characteristic of the beam current are satisfied, and a high quality color cathode ray tube can be constructed.

FIG. 2 shows a second embodiment of a color cathode ray tube according to the present invention.
1A and 1B are explanatory diagrams of a configuration of a control electrode and a cathode portion constituting an in-line type electron gun used in an embodiment, wherein FIG. 1A is a partial cross-sectional view, FIG. The same reference numerals correspond to the same parts.

In this embodiment, similarly to the above embodiment, the control electrode 3
1 is formed by joining a divided bottom portion 31a and a cup portion 31b, and the bottom portion 31a has a relatively low coefficient of thermal expansion of 42% N.
The cup portion 31b is made of a 49% Ni-Fe material having a relatively high coefficient of thermal expansion.

FIG. 5A is a view as seen from the in-line direction. As shown in FIG. 1, three cathodes K arranged in the in-line direction each accommodate a heater 21 and a heat dam 22 for ceramics or the like. Is integrated with the embedded fixing member 24 via the insulator 23 and fixed by welding to the inside of the control electrode 31.

The control electrode 31 has a substantially elliptical or horizontally long rectangular cup shape having a long axis in the in-line direction, and its length is parallel to the bottom surface 31a at a position close to the junction with the bottom surface 31a on the short side. Slit 3 partially cut on the side
1d is formed. Further, similarly to the above-described embodiment, each of the cathodes K is provided on the bottom surface 31a facing the acceleration electrode 32.
The electron beam passage holes 31aR, 31a
G, 31aB are formed.

In this configuration, the bottom surface 31a of the control electrode 31 where the electron beam passage holes 31aR, 31aG, 31aB are formed is made of a 42% Ni--Fe material having a relatively low coefficient of thermal expansion. 21 even when heated by the radiant heat of the heating of the inline direction.
(See FIG. 6) is suppressed, and the convergence deviation is significantly reduced.

On the other hand, since the cup portion 31b is made of a 49% Ni-Fe material having a relatively high coefficient of thermal expansion as in the prior art, all the deviations ΔLG in the Z-axis direction are made of 49% Ni-Fe material. This is the same as the conventional control electrode, and there is no deterioration in the rising characteristic of the beam current.

Further, since the slit 31d is formed, the displacement due to the thermal expansion does not exert a force to displace the bottom portion 31a in the in-line direction. The slits formed in the cup are not limited to those shown in the figures, but may be formed in the bottom 31.
The cut not parallel to a or the cut portion can be formed into an appropriate shape that does not affect the operation of the control electrode.

As described above, according to the present embodiment, both the reduction of the convergence deviation and the rising characteristic of the beam current are satisfied, and a high quality color cathode ray tube can be constructed.

In each of the embodiments described above, the joint between the cup part and the bottom part constituting the control electrode may be generally spot welded, but other appropriate fixing means may be used.

The present invention is applicable not only to the control electrode of an in-line type electron gun used for a color cathode ray tube, but also to a similar electrode whose characteristics are affected by thermal expansion.

[0058]

As described above, according to the present invention,
Deterioration of the characteristics affected by the thermal expansion of the electrodes constituting the electron gun can be suppressed.In particular, the convergence deviation after the start of operation in the control electrode of the in-line type electron gun and the rising characteristic of the beam current are compatible, and A color cathode ray tube capable of displaying an image of high quality can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the configuration of a control electrode and a cathode portion constituting an in-line type electron gun used in a first embodiment of a color cathode ray tube according to the present invention.

FIG. 2 is an explanatory view of a configuration of a control electrode and a cathode portion constituting an in-line type electron gun used in a second embodiment of the color cathode ray tube according to the present invention.

FIG. 3 is a cross-sectional view illustrating a structural example of a color cathode ray tube to which the present invention is applied.

4 is a partially broken side view illustrating an example of an in-line electron gun used in the color cathode ray tube shown in FIG.

FIG. 5 is a cross-sectional view of a main part explaining a structure of a triode of the in-line electron gun shown in FIG. 4;

FIG. 6 is a cross-sectional view of a main part in an in-line direction for explaining a deviation caused by thermal expansion in a conventional control electrode.

FIG. 7 is an explanatory diagram of an operation time versus current characteristic depending on a difference in a material of a control electrode.

FIG. 8 is a graph showing operation time vs. ΔLG due to a difference in control electrode material.
FIG. 4 is an explanatory diagram of a change characteristic.

[Explanation of symbols]

 Reference Signs List 20 cathode sleeve 21 heater 22 heat dam 23 insulating material 24 embedded fixing member 25 embedded portion 31 control electrode 31a bottom portion 31b cup portion 31aR, 31aG, 31aB electron beam passage hole 31d slit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sakae Ishii 3350 Hayano, Mobara-shi, Chiba Pref. Within Hitachi Electronics Devices, Ltd.

Claims (3)

[Claims] 1. A cathode having three cathodes for emitting three electron beams arranged in-line, a long axis in the in-line direction,
A rectangular cup-shaped control electrode having three electron beam passage holes facing the respective cathodes on the bottom surface, and the three cathodes are integrated via an insulator and embedded inside the control electrodes. A color cathode ray tube including a fixing member, an in-line type electron gun having at least an acceleration electrode, a focusing electrode, and an anode electrode arranged and fixed at a predetermined interval in the tube axis direction from the control electrode, wherein the control electrode is A color cathode ray tube comprising a bottom portion made of a metal material having a small thermal expansion coefficient and a cup portion made of a metal material having a large thermal expansion coefficient. 2. A slit according to claim 1, wherein a side wall surface substantially parallel to a short axis of said cup portion adjacent to said bottom surface portion of said control electrode is partially cut into a side wall surface substantially parallel to a long axis. A color cathode ray tube characterized by the above-mentioned. 3. The color cathode ray according to claim 1, wherein the metal material forming the bottom portion is 42% Ni-Fe, and the metal material forming the cup portion is 49% Ni-Fe. tube.