JP2002110056A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode-ray tube capable of rapidly getting out of a low picture quality state; in the cut-off voltages of three-color electron guns wherein it is difficult to uniformly constitute thereof to be forced to adjust bias voltages according to the characteristic of cathodes, even though, during a warming-up period until thermal deformation of electrode components reaches an equilibrium state, it is to a difficult to keep constant to reproduce in the low picture quality state. SOLUTION: A relation L2>L1 is set, where L2 is the length from a fixing point X, at which a cathode KG for a center beam is fixed on a cathode base 24, to an insulating member 24, and L1 is the length from a fixing point X, at which cathodes KB and KR for side beams are fixed on a cathode base 23, to the insulating member 24.

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 having an in-line type electron gun, and more particularly to a cathode structure capable of setting a cathode current value of each electron gun to a predetermined constant value in a short time from the start of operation. The present invention relates to a color cathode ray tube provided.

[0002]

2. Description of the Related Art At present, a color cathode ray tube generally used for a color television receiver, a color terminal display and the like includes a face panel 51 having a substantially rectangular screen as shown in FIG. An envelope having a funnel 52 integrally joined to the face panel 51 is provided. On the inner surface of the face panel 51, red, blue,
Phosphor screen 5 having a three-color phosphor layer that emits green light
3 are formed.

In the envelope, an electron beam passes through the inside of an opening 54 facing the phosphor screen 53, and a shadow mask 55 for performing color selection is provided in the face panel 51. Mask frame (not shown) on side
Further, an electron gun 57 for emitting an electron beam is provided in a neck 56 of the funnel 52, and the electron beam emitted from the electron gun 57 is attached to the outside of the funnel 52. The color image is reproduced on the phosphor screen 53 by being deflected by the magnetic field generated by the deflection yoke 58 and scanning the phosphor screen 53 in the horizontal and vertical directions with an electron beam.

The electron gun 57 includes three cathodes K (KB, KG, KR) arranged in a row in the horizontal direction, three heaters H inserted in each of the cathodes K, and a cathode K. First to seventh grids G1 to G7 of an integral structure sequentially arranged coaxially at predetermined intervals in the direction of the phosphor screen 53, and a convergence cup C fixed to the phosphor screen 53 side of the seventh grid G7. It is composed of

The first grid G1 is composed of cup-shaped electrodes, the second grid G2 is composed of plate-shaped electrodes, and the third to seventh grids G3 to G7 are each composed of a plurality of cup-shaped electrodes. The cathode K, the heater H, and the first to seventh grids G1 to G7 are
It has a structure integrally fixed by a pair of insulating glasses (not shown).

The neck 56 is provided with a stem 59 for sealing the inside of the envelope in a vacuum state. The stem 59 has a plurality of stem pins 60 which hermetically penetrate the stem 59. Further, an internal conductive film 61 is applied and formed from the funnel 52 of the envelope to the inner surface adjacent to the neck 56, and a valve spacer 62 pressed against the internal conductive film 61 is attached to the convergence cup C.

The voltage applied to each electrode of the electron gun 57 is applied to the electrodes other than the seventh grid G7 through the stem pin 60, and the seventh grid G7 is provided in the funnel 52 of the envelope. A high voltage is applied through an internal conductive film 61 connected to an anode terminal (not shown) and a valve spacer 62 pressed against the internal conductive film 61.

On the other hand, by forming the horizontal deflection magnetic field of the deflection yoke 58 as a pincushion type and the vertical deflection magnetic field as a barrel type, the three electron beams are made to self-converge, so that the dynamic convergence circuit can be omitted. , Reducing power consumption.

For this reason, the color cathode ray tube using the in-line type electron gun 57 greatly contributes to the improvement of the quality and performance of the color cathode ray tube, and is now widely used as a general color cathode ray tube.

The in-line type electron gun 57, particularly the cathode K portion, is configured as shown in FIGS. FIG. 6 is a cross-sectional view showing the cathode portion cut in the vertical direction, and FIG. 7 is a cross-sectional view showing the cathode portion cut in the horizontal direction.

That is, a cylindrical cathode K (KB, KG, KR) into which the heater H is inserted, three cathode supports 63 holding the cathode K, and a cathode support 6
An insulating member 64 for integrally holding the insulating member 3 and the insulating member 6
4, a metal cylinder 65 attached to the inner periphery of the first grid G1 and a cup-shaped first grid G1 for controlling the electron beam emitted from the cathode K, and a plate-like plate for accelerating the electron beam And the second grid G2 are arranged at a predetermined interval on the same axis and fixed by an insulating glass 66.

The length of each cathode support 63 in the tube axis direction is substantially the same for all three cathode supports 63, as shown in FIG. 63 is fixed at a location marked with a cross (fixed point) in the figure. The thickness of the surface of the insulating member 64 fixed to each cathode support 63 is also the same.

In a color cathode ray tube using such an in-line type electron gun 57, in order to obtain a good white screen, the cut-off voltages of the blue, green and red electron guns 57 are made the same. That is, the cathode current value (IK value) of each cathode K is designed to be a predetermined constant value.

However, in general, the cut-off voltage of each electron gun 57 is not always the same due to variations in parts and differences in the coefficient of thermal expansion. For this reason, in order to set each IK value to a predetermined constant value, After assembling the cathode ray tube into the color cathode ray tube device, by adjusting the bias voltage according to the characteristics of each cathode K, the equivalence between the respective IK values is obtained.

Even if such measures are taken to ensure the equality of the IK values, during the warm-up period from when the heater H of the color cathode ray tube is energized to when the thermal deformation of each electrode component reaches an equilibrium state. In the above, each IK value cannot be set to a predetermined constant value. In other words, this is because the setting by adjusting the bias voltage is set after the warm-up period ends. The time required for this warm-up requires about 20 minutes after the energization.

That is, when the heater H is energized and each member reaches a thermal equilibrium state, the cathode K is connected to the cathode support 6.
3 operates in a higher temperature range, and the cathode support 63 operates in a higher temperature range than the insulating member 64. In other words, the rate of temperature rise during the warm-up period is higher than that of the insulating member 64 supporting the cathode support 63.
3 is earlier, and the cathode K is earlier than the cathode support 63.

As a result, each electrode component of the electron gun 57 changes with different characteristics due to thermal expansion at different temperature rising rates. The state of this change will be described with reference to FIGS. FIG. 8 is a vertical cross-sectional view showing the direction of extension of the electrode components constituting the three-electrode portion due to thermal expansion. The arrows in the figure show the directions of extension of the corresponding components, respectively. It is a characteristic curve showing the elongation of each part of the cathode K and the first grid G1 with respect to the change. Among the reference numerals assigned to the respective characteristic curves, A to C correspond to the reference numerals attached to the arrows in FIG.

As shown by an arrow A in FIG.
Is increased by the temperature rise during the warm-up period.
It extends in the direction of one grid G1 with the characteristics shown by the curve A in FIG. On the other hand, the cathode support 63 extends in a direction away from the first grid G1 as shown by an arrow B in FIG. 8 with a characteristic shown by a curve B in FIG. Further, the first grid G1 extends in a direction away from the cathode K as shown by an arrow C in FIG. 8 with a characteristic shown by a curve C in FIG.

Here, the cathode K, the cathode support 6
3, and the thermal change in the cathode structure including the insulating member 64 that supports them, is that the cathode K and the cathode support 63 are disposed close to the heater H, and that the cathode K and the cathode support 63 are configured using a thin plate. Therefore, thermal equilibrium is reached in a relatively short time, about 30 seconds after energization at the cathode K and about 3 minutes at the cathode support 63.

On the other hand, the first grid G1 reaches the thermal equilibrium state after about 15 minutes have passed since the energization, and after the first about 3 minutes of the warm-up period. The interval between the cathode K and the first grid G1 changes mainly due to the change of the first grid G1.

Therefore, the interval between the cathode K structure and the first grid G1 during the warm-up period changes as shown by a curve D in FIG. 9 under the influence of the thermal expansion of each component described above.

As described above, during the warm-up period,
Since the interval between the cathode K and the first grid G1 changes, it takes about 15 minutes from when the heater H is energized until each component reaches an operating temperature equilibrium state.

After the warm-up, the bias voltage is adjusted so as to correct the uneven spacing between the electrodes so that the IK values of the three cathodes K are maintained equal. After being incorporated, the set bias voltage cannot be changed. For this reason, there arises a problem that the equivalence of the once set IK value cannot be achieved until the operating temperature reaches the equilibrium state.

FIG. 10 is an IK value curve showing a change with time from the energization after the bias voltage adjustment until each IK value becomes a predetermined constant value. The figure shows that the bias voltage is adjusted after warm-up, and the center beam cathode KG at the center, the side beam cathodes KR at both outer sides,
The graph shows the change in the cathode K current after the heater H has been energized after sufficient cooling with the respective cathode currents of KB set to 10 μA, and then only the heater H voltage turned off. In the figure, a curve 1 shows the IK value characteristic of the cathode KG arranged at the center among the three cathodes K arranged in line, and a curve 2 shows the IK value characteristics of the other two cathodes KB and KR. The IK value characteristic is shown.

As described above, the reason why each IK value characteristic differs between the curves 1 and 2 is that the temperature and heat of the electrode parts constituting the cathode assembly are determined by the arrangement of the electrode parts around each cathode K as described above. This is due to the difference in expansion between the central cathode KG and the outer cathodes KB, KR.

In FIG. 10, both the curve 1 and the curve 2
The change in the IK value for about 30 seconds after the heater H is energized is governed by the cathode K extending in the direction of the first grid G1, and for about 30 seconds to about 3 seconds after the heater H is energized.
The change in the IK value during the period is governed by the cathode support 63 extending in the direction away from the first grid G1, and the change in the IK value after about three minutes after the heater H is energized is mainly caused by the first change. It changes under the control of the thermal deformation of the grid G1.

As described above, since the state before returning to the set IK value after warming up is different, 3
It takes approximately the same time as the warm-up period until a good white screen is obtained by obtaining the same IK value for each cathode K.

Therefore, it takes a considerable amount of time to obtain a good white screen after energizing the color cathode ray tube,
Further, since the bias voltage adjusted after the warm-up is difficult to change thereafter, the equivalence between the IK values once set only after the parts reach the equilibrium state of the operating temperature. That it takes a long time to get a good white screen,
This means that the low image quality time in use is longer.

In order to solve such a problem, the cathode support 63 disposed at the center of the three cathode supports 63 and the two cathode supports 63 on both sides are made of materials having different thermal expansion coefficients. Is theoretically conceivable, but the cathode support 63 and the insulating member 6 for fixing the same are used.
If the coefficients of thermal expansion of the respective members 4 are different from each other, the fixing strength of both members is reduced, and cracks occur in the insulating member 64 for fixing the cathode support 63, and in the worst case, the cathode support 64 is dropped off. Therefore, it has been difficult to realize it with an actual product.

For this purpose, conventionally, the material of the cathode support 63 and the material of the insulating member 64 for fixing the cathode support 63 are made of a Kovar material (29% N
Since i- 17% Co-Fe) can only be used to constitute a single cathode support 63 as a whole, it is not possible to obtain the same IK value for the three cathode K cathodes. Was.

[0031]

As described above, conventionally, it takes a considerable time until a good white screen is obtained after the color cathode ray tube is energized, and as a means for solving this problem, It is conceivable to change the material of the cathode support 63, but it is extremely difficult to realize the material because of the combination of the mechanical holding strength with the insulating member 64.

The present invention has been made in order to solve such a problem, and without changing the material of the cathode support,
It is an object of the present invention to provide a color cathode ray tube capable of obtaining a good white screen by setting each IK value to a predetermined constant value in a short time after energization.

[0033]

SUMMARY OF THE INVENTION The present invention provides a face panel having a phosphor screen having a three-color phosphor layer disposed on an inner surface, a funnel having a neck connected to the face panel, and an outer peripheral portion of the funnel. An in-line type electron gun arranged in a line in a neck for emitting a center beam and a pair of side beams to a phosphor screen, which are horizontally and vertically deflected by a deflection yoke attached to the electron screen. The length L2 from the fixed point of the center beam cathode and the cathode support to the insulating member holding the cathode support, and the cathode support is held from the fixed point of the side beam cathode and the cathode support The length L1 to the insulating member is represented by L2>
L1 was set.

With this configuration, the equivalence of the final three cathodes is adjusted by the step of the insulating member without changing the materials used for the cathode support individually, and the IK value is adjusted. Are made substantially equal for the three cathodes, it is possible to greatly reduce the matching time of the IK value of each cathode.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the color cathode ray tube of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the color cathode ray tube includes a face panel 11 having a substantially rectangular screen, and an envelope having a funnel 12 integrally joined to the face panel 11. On the inner surface of the face panel 11, a phosphor screen 13 having a three-color phosphor layer that emits red, blue, and green light is formed.

In the envelope, an electron beam passes through the inside of the opening 14 opposite to the phosphor screen 13 and a shadow mask 15 for performing color selection is provided in the face panel 11. It is attached to the side via a mask frame (not shown), and furthermore, the neck 1 of the funnel 12
An electron gun 17 that emits an electron beam is disposed in the electron beam 6. The electron beam emitted from the electron gun 17 is deflected by a magnetic field generated by a deflection yoke 18 mounted outside the funnel 12, By scanning the phosphor screen 13 in the horizontal and vertical directions with the beam, a color image is reproduced on the phosphor screen 13.

The electron gun 17 includes three cathodes K (KB, KG, KR) arranged in a row in the horizontal direction, three heaters H inserted into the respective cathodes K, and a cathode K. First to seventh grids G1 to G7 of an integral structure sequentially arranged coaxially at predetermined intervals in the direction of the phosphor screen 13, and a convergence cup C fixed to the phosphor screen 13 side of the seventh grid G7. It is composed of

The first grid G1 is composed of cup-shaped electrodes, the second grid G2 is composed of plate-shaped electrodes, and the third to seventh grids G3 to G7 are each composed of a plurality of cup-shaped electrodes. The cathode K, the heater H, and the first to seventh grids G1 to G7 are
It has a structure integrally fixed by a pair of insulating glasses (not shown).

The neck 16 is provided with a stem 19 for sealing the inside of the envelope in a vacuum state, and a plurality of stem pins that penetrate the stem 19 in an airtight manner are implanted in the stem 19. Further, an internal conductive film 21 is applied and formed from the funnel 12 of the envelope to the inner surface adjacent to the neck 16, and a valve spacer 22 pressed against the internal conductive film 21 is attached to the convergence cup C.

The voltage applied to each electrode of the electron gun 17 is applied to the electrodes other than the seventh grid G7 through the stem pin 20, and the seventh grid G7 is provided on the funnel 12 of the envelope. Internal conductive film 21 connected to an anode terminal (not shown) and internal conductive film 2
A high voltage is applied via the valve spacer 22 that is pressed against the first spacer 1.

On the other hand, by forming the horizontal deflection magnetic field of the deflection yoke 18 into a pincushion type and the vertical deflection magnetic field into a barrel type, the three electron beams are made to self-converge.

The in-line type electron gun 17, particularly the cathode K portion, is configured as shown in FIG.

That is, a cylindrical cathode K (KB, KG, KR) into which the heater H is inserted, three cathode supports 23 holding the cathode K, and the cathode support 2
An insulating member 24 for integrally holding the insulating member 3 and the insulating member 2
4, a metal tube 25 attached to the inner periphery of the first grid G1 and a cup-shaped first grid G1 for controlling an electron beam emitted from the cathode K, and a plate-like plate for accelerating the electron beam Is separated from the second grid G2 by a predetermined distance on the same axis, and is fixed by the insulating glass 26.

The length of each cathode support 23 in the tube axis direction is substantially the same for all three cathode supports 23, and each cathode K and cathode support 23 are indicated by x in the figure.
It is fixed at the mark (fixed point). Then, the insulating member 24 is compared with the thickness D2 of the peripheral edge portion of the cathode support member 23 holding the central center beam cathode KG, and the peripheral edge of the cathode support member 23 holding the outer side beam cathodes KB and KR. Part thickness D1 is large, D1> D
The insulating member 24 has a step having a shape of 2.

By using this insulating member 24,
The distance in the tube axis direction between the surface of the insulating member 24 on the side opposite to the cathode K disk and the fixing point x between the cathode support 23 and the cathode K is set to the distance between the outer periphery of the cathode KB and KR. Compared to the distance L1 between the body 23 and the fixed point x between the cathodes KB and KR, the distance L2 between the cathode support body 23 at the periphery of the central cathode KG and the fixed point x between the cathode KG can be made longer. .

In this embodiment, the thickness of the insulating member 24 is set to D1 = 2.5 mm and D2 = 2.0 mm, and the surface of the insulating member 24 on the side opposite to the cathode K disk and the cathode support 23 The distance between the fixed point x and the cathode K in the tube axis direction is set to L1 = 2.5 mm and L2 = 3.0 mm, and the material to be used for each of the cathode supports 23 is made of Kovar material.

In a color cathode ray tube manufactured by a general manufacturing method using such an electron gun 17 structure, the cathode support 23 for the center cathode KG is attached to the cathode KB and KR support 23 on both outer sides. In comparison, the distance in the tube axis direction between the surface of the insulating member 24 opposite to the electron beam emission surface of the cathode K and the fixed point x between the cathode support 23 and the cathode K is set to L2> L1. As long as L2 is longer than L1, the center cathode KG by warming-up is compared with both outer cathodes KB and KR.
It extends more in the direction away from the first grid G1.

Therefore, the bias voltage after the warm-up is changed between the central cathode KG and the outer cathodes KG.
When the heaters H are sufficiently cooled and the heater H is energized, the distance between the first grid G1 and the cathode K is equal to the distance between the outer cathodes KB and KB.
The central cathode KG portion is narrower than the KR portion.

That is, after sufficiently cooling, the heater H
When the first grid G1 and the cathode support 23 are still energized, the cathode K current is dominated by the extension of the cathode K for about 30 seconds from the energization until the first grid G1 and the cathode support 23 operate. The distance between the first grid G1 and the cathode KG in the central cathode KG portion is relatively smaller than the distance between the first grid G1 and the cathodes KB and KR in the outer cathode KB and KR portions. More cathode current flows in the central cathode KG.

As a result, as shown in FIG. 3, after the warm-up, the bias voltage is adjusted to set the respective cathode K currents of the central cathode KG and the outer cathodes KB and KR to 10 μA, and thereafter the heater H After sufficiently cooling with only the voltage turned off, the change in the cathode K current after the heater H is turned on is determined by the change in the center cathode K
As shown by the curve 1 in the graph of the IK value characteristic of G, the cathode KG current value at the initial stage of warming-up flows more than the cathode current of the conventional central cathode KG, and the cathode KB, KR of both outer cathodes KB and KR. When the thickness D1 of the insulating member 24 is set to the same thickness as the conventional one, the KR current becomes the same value as the conventional one.
This is similar to the IK value characteristics of the cathodes KB and KR on both outer sides shown by.

Therefore, when the color cathode ray tube of the present invention is energized by being incorporated in a cathode ray tube device, it is possible to display a screen and to reproduce a good image display in which the low image quality time is greatly reduced.

In general, the material of the insulating member 24 includes amorphous glass, crystalline glass, and borosilicate glass. Amorphous glass has low mechanical and thermal strength, but is chemically durable. By using a crystalline glass and a borosilicate glass having a strong property and a fixing strength, the cathode support 23 and the cathode K, and the metal cylinder 2 surrounding these are supported.
5, a cathode structure having a high holding strength can be obtained.

FIG. 4 is a cross-sectional view showing a cathode K portion showing another configuration of the present invention, which is cut in the vertical direction. The same components as those in the above embodiment are denoted by the same reference numerals.
Detailed description is omitted.

In the embodiment shown in FIG. 4, the thickness D of the peripheral portion of the cathode KG support 23 at the center of the insulating member 24 is
2 and the thickness D1 of the peripheral portion of the support 23 of both outer cathodes KB and KR are set to the same thickness D2 = D1. The cathode KG support 2 at the center of the insulating member 24
By making the three peripheral portions project in the direction of the first grid G1 to have a concave step on the stem 19 side, the surface of the insulating member 24 opposite to the cathode K disk, the cathode support 23 and the cathode The distance in the tube axis direction from the fixed point X of K is larger than the distance L1 in the tube axis direction between the cathode support 23 at the peripheral edge of both outer cathodes KB and KR and the fixed point X of the cathode KB and KR. The distance L2 in the tube axis direction between the cathode support 23 at the periphery of the cathode KG and the fixed point x of the cathode KG is long, and L2> L1.

With such a configuration, L2
> L1, the same effect as in the above embodiment can be exerted.

The present invention is not limited to the above embodiment. For example, the central concave portion of the cathode KG support may be formed not in a step-like step but in a mortar-like oblique shape. For each grid configuration and form,
Other configurations are also possible, other various applications,
It goes without saying that deformation is possible.

[0058]

According to the present invention, since the IK value characteristics between the center beam and side beam cathodes can be approximated, each IK value can be set to a predetermined constant value in a short time after adjusting the bias voltage. And the time required to obtain a good white screen after energizing the color cathode ray tube can be greatly reduced, so that the playback time in a low image quality state is shortened,
A high-quality reproduced image can be obtained quickly, and the productivity of the color cathode ray tube and the color cathode ray tube device incorporating the color cathode ray tube can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a color cathode ray tube according to the present invention.

FIG. 2 is a cross-sectional view showing a configuration example of a cathode portion constituting a color cathode ray tube according to the present invention.

FIG. 3 is a characteristic diagram showing cathode current characteristics of the color cathode ray tube according to the present invention.

FIG. 4 is a cross-sectional view showing another example of the configuration of the cathode portion constituting the color cathode ray tube according to the present invention.

FIG. 5 is a sectional view showing a conventional color cathode ray tube.

FIG. 6 is a cross-sectional view showing a structure of a cathode portion constituting a conventional color cathode ray tube, cut in a vertical direction.

FIG. 7 is a cross-sectional view showing the configuration of the cathode portion cut in the horizontal direction.

FIG. 8 is a cross-sectional view for explaining an extension direction due to thermal expansion of each electrode component constituting the cathode portion.

FIG. 9 is a characteristic diagram showing elongation of each electrode component with respect to time-dependent change.

FIG. 10 is a characteristic diagram showing cathode current characteristics.

[Explanation of symbols]

 11: face panel 12: funnel 13: phosphor screen 16: neck 17: electron gun 18: deflection yoke KG: cathode for center beam KB, KR: cathode for side beam 23: cathode support 24: insulating member

Claims (3)

[Claims] 1. A face panel having a phosphor screen having a three-color phosphor layer disposed on an inner surface thereof, a funnel having a neck connected to the face panel, and a deflection yoke mounted on an outer peripheral portion of the funnel. And an in-line type electron gun arranged in a line in the neck for emitting a center beam and a pair of side beams deflected in the vertical direction to the phosphor screen, for the center beam constituting the electron gun. The length L2 from the fixing point between the cathode and the cathode support to the insulating member holding the cathode support, and the length from the fixing point between the side beam cathode and the cathode support to the insulating member holding the cathode support. A color cathode ray tube wherein L1 is set so that L2> L1. 2. The thickness D2 of the insulating member for holding the cathode support for the center beam and the thickness D1 of the insulating member for holding the cathode support for the side beam are set to D1> D2. 2. The color cathode ray tube according to claim 1, wherein a relationship of L2> L1 is satisfied. 3. The thickness of the insulating member for holding the cathode supports for the center beam and the side beams is made equal, and the insulating member on the periphery of the cathode support for the center beam is displaced toward the phosphor screen. 2. The color cathode ray tube according to claim 1, wherein L2> L1.