JPH1131462A - Cathode-ray tube and manufacture of its color selecting mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a color cathode-ray tube having a high definition by increasing the thickness of a color selecting mask to restrict the mislanding of electron beam and reducing the arrangement pitch of openings. SOLUTION: In this method, an electron gun 3, an aperture grille (a color selecting mask) 21 having slits (openings) 22A, 22B, 22C... to pass electron beam 16 emitted from the electron gun 3 therethrough and phosphor stripes 24 colored with the electron beam 16 passed through the aperture grille 21 are provided. A thickness (t) and an arrangement pitch P are defined for the aperture grille 21 to be 0.5<=t/P<=1.0, where the thickness of the aperture grille 21 is (t) and the arrangement pitch of the slits 22A, 22B, 22C... in the aperture grille 21 is P.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube suitably applied to a color cathode ray tube having a color selection mechanism and a method of manufacturing a color selection mask therefor. More specifically, by increasing the thickness of the color selection mask, it is possible to suppress the mislanding of the electron beam, and by reducing the arrangement pitch of the apertures, it is possible to produce a high-definition color CRT. And a method for manufacturing a color selection mask for the same.

[0002]

2. Description of the Related Art A color cathode ray tube (hereinafter referred to as a color CRT)
), The three electron beams emitted from the electron gun and corresponding to, for example, three primary color signals are formed inside the phosphor glass panel by controlling the beam irradiation width (arrival diameter) by the color selection mask. By landing on the red (R), green (G), and blue (B) phosphors, the phosphors emit light.

[0005] Therefore, a color shift may occur due to a landing error of the electron beam on the phosphor. In order to reduce the color shift, a conventional color CRT employs a configuration in which carbon, which is a black non-light emitting substance, is embedded between phosphors of each color on a phosphor screen. This carbon coating provides a margin for landing of the electron beam, so that color shift can be improved.

FIG. 7 is a perspective view of a color CRT having a color selection mask called an aperture grill, that is, a so-called Trinitron (trade name) type CRT. This color C
An aperture grill (A) having a well-known interdigital linear body 11 as shown in FIG.
G) 2 is provided.

The upper and lower portions of the aperture grill 2 have A
A pair of AG frame A members 8 constituting a G frame
A pair of AG frame B members 9 constituting an AG frame are mounted on the left and right portions thereof, and are supported so as to pull the aperture grill 2 up, down, left, and right with great force.

An aperture grill (color selection electrode) 2 is constituted by the AG frame A member 8, the AG frame B member 9 and the linear body 11, and the plate springs 7 are provided on the AG frame A member 8 and the AG frame B member 9, respectively. Is attached.

A phosphor glass panel 1 having stud pins is provided on the front side of the aperture grill 2, and the aperture grill 2 is supported by engaging a spring 7 with the stud pins. Red on the inside of the panel,
Phosphor stripes of three colors of green and blue are formed. An integrated funnel 4 is joined to the phosphor glass panel 1 via a frit seal 10, and the electron gun 3 is sealed in the funnel 4.

[0008] The aperture grill 2 is formed as follows. As shown in the cross-sectional view of FIG. 8, first, resist films 13 and 14 are patterned on the front and back of an iron plate (hereinafter simply referred to as iron plate 11) to be a linear body 11.
The iron plate 11 is isotropically etched while masking the masks 3 and 14 one by one. At this time, the surface of the iron plate 11 (the emission surface 11B of the electron beam) to the back surface (the electron beam incidence surface 11B).
The groove portion etched toward A) and the iron plate 11
Is etched toward the groove from the back surface of the substrate, and the boundary edge portion with the opening that penetrates the groove is the control edge 12A, 1
2B, 12C...

The control edges 12A, 12B, 12C.
··· Red, green and blue phosphor stripes (or dots) of three electron beams emitted from the electron gun 3
(The irradiation width of the electron beam) is controlled. As a result, the red display electron beam collides with the red phosphor to emit light, and the green and blue display electron beams emit green and blue light, respectively.
A color image can be displayed by colliding with the blue phosphor and illuminating only the phosphor.

By the way, it is known that an electron beam is affected by an external magnetic field such as terrestrial magnetism, so that the electron beam deviates from a predetermined phosphor and causes a resultant color shift. This phenomenon is called mislanding of the electron beam due to terrestrial magnetism.

As means for suppressing the mislanding, an internal magnetic shield plate (I) is provided on the inner wall (specific section) of the CRT from the cone portion of the funnel 4 to the color selection electrode 2.
MS) 5 or an external magnetic shield plate (OMS) outside the CRT. The internal magnetic shield plate 5 and the external magnetic shield plate are formed of a quadrangular pyramid-shaped frame made of a thin metal plate having ferromagnetism, and have a feature of being able to shield an electron beam in the above-described specific section from an external magnetic field such as geomagnetism. ing.

[0012]

In a recent color CRT, an electron beam passing through the control edge of the aperture grill 2 in addition to the above-described specific section scatters a very large amount of beam due to terrestrial magnetism while reaching the phosphor stripe. Was found to occur. Therefore, in order to suppress the color shift of the color CRT, it is necessary to shield from the geomagnetism while reaching the phosphor stripe from the control edge of the aperture grill 2.

As one of the shield methods, a method using the linear body 11 of the aperture grill 2 itself has been considered. This is, as shown in FIG.
Control edges 12A, 12b, 12C
Are formed to regulate the beam diameter, and the distance L from each of the control edges 12A, 12B, 12C... To the beam exit surface 11B is used as a beam shield portion.

On the other hand, in order to increase the definition of the CRT, as shown in FIG.
It is necessary to reduce the arrangement pitch P between the slits 15B, between the slits 15B, 15C,....

However, in order to reduce the arrangement pitch P, sharp control edges 12A, 12B, 12C
In order to obtain..., The thickness t of the aperture grill (hereinafter also referred to as a color selection mask) 2 must be reduced. Therefore, when the plate thickness t is reduced, the shield distance L is shortened, the effect of suppressing the mislanding of the electron beam due to the terrestrial magnetism is reduced, and a color shift is caused.

As a result, there is a problem that it is difficult to improve the effect of suppressing mislanding and to manufacture a color CRT with high definition.

Accordingly, the present invention has been made in view of the above problem, and it is possible to suppress the mislanding of the electron beam by increasing the thickness of the color selection mask, and to arrange the aperture pitches of the apertures. It is an object of the present invention to provide a cathode ray tube capable of producing a high-definition color cathode ray tube by reducing the size of the cathode ray tube and a method of manufacturing a color selection mask thereof.

[0018]

In the cathode ray tube of the present invention, an electron gun, a color selection mask having a plurality of apertures for passing an electron beam emitted from the electron gun, and the color selection mask And a phosphor that emits a color due to the electron beam passing therethrough. When the thickness of the color selection mask is t, and the arrangement pitch of the apertures of the color selection mask is P, the color selection mask is 0.5 ≦ t / The thickness and the arrangement pitch are defined so that P ≦ 1.0.

In the cathode ray tube of the present invention, by increasing the thickness of the color selection mask, the shield distance to the terrestrial magnetism can be increased, so that mislanding of the electron beam can be suppressed. At the same time, by reducing the arrangement pitch of the apertures of the color selection mask, the pitch of the apertures of the color selection mask can be made finer, so that a high-definition color CRT can be produced.

In the method for manufacturing a color selection mask for a cathode ray tube according to the present invention, when the first surface of the metal plate is used as an electron beam incident surface and the second surface of the metal is used as an electron beam emission surface, the second surface of the metal plate is used. Patterning a resist film having a first opening width on one surface at a predetermined arrangement pitch, and patterning a resist film having a second opening width on the second surface of the metal plate at substantially the same arrangement pitch; A step of applying a filler on the entire first surface of the metal plate, a step of etching the metal plate with an isotropic etching solution using a resist film having a second opening width as a mask, and removing the filler. And etching the metal plate with an isotropic etching solution using the resist film having the first opening width as a mask.
This metal plate is over-etched from the second surface of the metal plate by making the time for performing the isotropic etching from the second surface longer than the time for performing the isotropic etching from the surface.

According to this manufacturing method, the time for performing isotropic etching from the second surface, which is the emission surface of the electron beam, to the inside is the time for performing isotropic etching from the first surface, which is the incidence surface. Since the length is set to be longer than that, it is possible to perform over-etching such that the metal plate under the resist film patterned on the second surface is covered.

Therefore, the opening of the metal plate formed by performing the isotropic etching from the second surface and the opening formed of the metal plate formed by performing the isotropic etching from the first surface. Boundary edge (corresponds to the control edge of the electron beam)
Can be formed at a position close to the incident surface of the electron beam,
The distance from the boundary edge to the emission surface of the electron beam can be made longer than in the conventional method of manufacturing a color selection mask.

As a result, since the shield distance to the earth magnetism becomes longer, mislanding of the electron beam can be suppressed, and the arrangement pitch of the apertures of the color selection mask is less than 0.25 mm. Degree color CRT can be manufactured.

[0024]

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

FIG. 1 is a diagram showing a configuration example of a cathode ray tube as an embodiment of the present invention. In the cathode ray tube of the present embodiment, by increasing the thickness of the aperture grill as a color selection mask, it is possible to suppress the mislanding of the electron beam and to reduce the arrangement pitch of the apertures, thereby increasing the height. A color CRT with high definition can be created.

A cathode ray tube (hereinafter referred to as a color CRT) having an aperture grill as a color selection mask to which the present invention is applied.
7) and the method of attaching the aperture grill to the phosphor glass panel, the configuration and the attachment method described with reference to FIG. 7 can be applied, and a description thereof will be omitted.

As shown in FIG. 1, the color CRT according to the present embodiment has an aperture grill 21 for controlling the arrival diameter of the electron beam 16 emitted from the electron gun 3, as shown in FIG.
Are provided on the side of the phosphor stripe 24 of the phosphor glass panel 1, and a plurality of apertures (hereinafter, referred to as slits) 22A, 22B, 22C,.
Is provided.

As shown in the sectional view of FIG. 2, the aperture grill 21 has an incident surface 21A on which the electron beam 16 is incident.
An emission surface 21B for emitting an electron beam, and control edges 23A, 23B, 23C,... For controlling the arrival diameter of the electron beam 16 for each of the slits 22A, 22B, 22C.
・ It has The control edge 23A has a groove formed by isotropic etching from the incident surface 21A of the electron beam 16 to the emission surface 21B,
Is formed by a boundary edge with an opening portion penetrating the groove portion etched from the exit surface 21B to the entrance surface 21A.

In this embodiment, the control edges 23A,
Are formed closer to the incident surface 21A of the electron beam 16 than in the conventional method, and the control edges 23A, 23
Opening portions reaching B, 23C,... Have a cross-sectional shape over-etched.

Assuming that the thickness of the aperture grill 21 is t and the arrangement pitch between the slits 22A, 22B, 22B, 22C,... Is P, unlike the conventional method, 0.5 ≦ t / P ≦ 1. The thickness t and the arrangement pitch P of the aperture grill 21 are defined so as to be zero.

When t / P is defined in the range of 0.5 to 1.0 as described above, the thickness t of the aperture grill 21 is increased, and the width of the resist opening at the time of forming the slit is reduced, so that the aperture is reduced. The shield distance L from the control edge of the grill 21 to the beam exit surface can be increased.

The longer the shield distance L, the more the electron beam 16 emitted from the electron gun 3 is controlled by the control edges 23A, 23A of the aperture grill 21 as shown in FIG.
Even after passing through 23B, 23C,..., The electron beam is shielded from the earth magnetism for a long time, so that mislanding of the electron beam 16 can be suppressed.

At the same time, by reducing the arrangement pitch P between the slits 22A and 22B, between the slits 22B and 22C of the aperture grill 21, the slit 22A of the aperture grill 21 having a fine pitch as shown in FIG. , 22B, 22C,.
6 can display a color image by colliding with the red, green, and blue phosphor stripes (dots in a shadow mask tube) 24 to form a color, so that a high-definition color cathode ray tube can be produced.

Next, a method of manufacturing a color selection mask for a cathode ray tube according to the present invention will be described with reference to the sectional views of FIGS. For example, when forming an aperture grill 21 of a 19-inch color CRT, the size is vertical x horizontal =
An iron plate 21 of about 274 mm × 366 mm and having a plate thickness t = 0.13 mm is prepared as shown in the sectional view of FIG. 4A.

When one surface of the iron plate 21 is an incident surface (first surface) 21A of the electron beam and the other surface of the iron plate 21 is an emission surface (second surface) 21B of the electron beam, about 1384 In order to form a book slit, as shown in FIG. 4B, a predetermined arrangement pitch P
The resist film 25 having a first opening width φ1 of about 0.12 mm and a thickness of about 0.25 mm is patterned.

Further, a resist film 26 having a second opening width φ2 of about 0.08 mm is patterned at substantially the same arrangement pitch P on the second surface of the iron plate 21. The opening width φ2 of the resist film 26 is made smaller than the opening width φ1 of the resist film 25 in order to leave the boundary wall between the slits and to overetch the iron plate 21 from the first surface side.

Next, as shown in FIG. 4C, a filler 27 is applied to the entire surface of the iron plate 21 on the first surface side. Filler 2
Reference numeral 7 is for preventing the first surface from being etched when the second surface is etched. A thing like a varnish is used for the filler 27.

Thereafter, as shown in FIG. 5A, the iron plate 21 is over-etched from the second surface side with an isotropic etching solution using the resist film 26 on the second surface side as a mask. The reason why the second surface side is etched first is to form the control edge of the electron beam on the incident surface side as much as possible.
By the way, if the first surface side is etched first, the control edge shifts to the emission surface side when etching from the second surface side. An aqueous solution of ferric chloride is used as an etching solution.

The etching time θ2 is about 60 minutes.
At this time, the time θ for performing isotropic etching from the first surface side
The time θ2 during which the iron plate 21 is isotropically etched from the second surface side is set to be longer than that of the case of FIG. In this example, θ
1: θ2 = 1: 4. By this isotropic etching, stripe-shaped grooves 22A, 22B and 2 are formed on the second surface side.
2C are formed.

On the iron plate 21, grooves 22A, 22B, 22C
.. is formed, as shown in FIG.
7 is removed with a weakly alkaline aqueous solution, and then the first
Using the resist film 25 on the surface as a mask, the iron plate 21 is etched with the above-described isotropic etching solution. The etching time is about 15 minutes. By this etching, stripe-shaped openings (which become slits in this step) penetrating the above-mentioned grooves 22A, 22B, 22C... Are formed, and a control edge for controlling an electron beam by a boundary edge of the slits. 23A, 23B,
23C... Are defined. This control edge 23A, 2
The opening width φ3 of 3B, 23C,... Determines the electron beam transmittance τ = (φ3 / P) × 100%. In this example, the transmittance τ is set to about 22 to 26%.

Thereafter, the iron plate 21 is coated on both sides of the resist film 2.
5, 26 are removed with an alkaline aqueous solution, and then
By cleaning the iron plate 21 with pure water, an aperture grill 21 as shown in FIG. 5C is formed. The AG frame is attached to the upper and lower portions and the left and right portions of the formed aperture grill 21 as in the conventional method, and a so-called Trinitron (trade name) type CRT color selection mask is completed (see FIG. 7).

As described above, in the method of manufacturing a color selection mask for a cathode ray tube according to the present invention, the iron plate 21 is placed on the electron beam incident surface (the first surface).
The iron plate 21 is placed on the electron beam emission surface (second surface) 21B longer than the time θ1 for performing isotropic etching from the surface 21A.
By increasing the time θ2 for performing the isotropic etching by about 4 times, overetching such that the iron plate 21 under the resist film 26 patterned on the electron beam emitting surface 21B could be performed was performed.

FIGS. 6A and 6B are sectional views comparing a method of manufacturing the aperture grill 2 according to the conventional method and a method of manufacturing the aperture grill 21 according to the present embodiment.

The process conditions of the present embodiment and the conventional system are as follows. The arrangement pitch P is 0 in both the present embodiment and the conventional method.
The etching method was isotropic etching using an aqueous solution of ferric chloride. However, in the conventional method, normal etching was performed without over-etching, and in this embodiment, over-etching was performed.

In this embodiment, in order to perform over-etching, the opening width φ2 of the resist film 26 on the side of the electron beam emission surface 21B is set to be 30 to 40 times smaller than the conventional opening width φ2 ′.
%, And the etching time from the electron beam emission surface 21B side is increased by about 1.5 times as compared with the conventional method. Under these process conditions, a comparison was made as to which one could form an aperture grille with a large plate thickness t.

According to this, in the conventional aperture grill 2, as shown in FIG. 6A, the electron beam exit surface 11B
Since the steel plate 11 was not subjected to over-etching, the thickness t1 was 0.1 mm at the maximum. The ratio t / P of the arrangement pitch P to the plate thickness t1 is 0.1.
459, which was 0.5 or less.

On the other hand, in the aperture grill 21 of the present embodiment, as shown in FIG.
Since the over-etching was performed so that the iron plate 21 was circulated from B, the plate thickness t2 could be set to 0.13 mm. The ratio t / P of the arrangement pitch P to the thickness t2 is 0.6.
39, that is 0.5 ≦ t / P ≦ 1.0.

In the conventional method, the shield distance L1, which is the distance from the electron beam control edge 11A to the electron beam emission surface 11B, was 0.07 mm. On the other hand, in the present embodiment, the shield distance L2 is 0.1 mm,
It could be lengthened by 0.03 mm.

As a result, the mislanding due to terrestrial magnetism could be improved by about 30% in this embodiment as compared with the conventional method. Moreover, in the aperture grill 21 of the present embodiment, the control edge can be further lowered to the electron beam incident surface 21A side as compared with the conventional method.

As described above, according to the present embodiment, a high-definition color cathode ray tube having a color selection mask having a plate thickness t of 0.13 mm and an arrangement pitch of 0.25 mm could be manufactured.

Although the embodiment of the present invention has been described with reference to an aperture grill as a color selection mask,
Similar effects can be obtained in a shadow mask tube provided with a color selection mask such as a delta type circular mask or an inline type slot mask.

[0052]

As described above, in the cathode ray tube of the present invention, when the thickness of the color selection mask is t and the arrangement pitch of the apertures of the color selection mask is P, 0.5 ≦ t / P ≤
The thickness and arrangement pitch of the color selection mask are defined so as to be 1.0.

Therefore, by increasing the thickness of the color selection mask, it is possible to increase the shield distance to the terrestrial magnetism between the color selection mask and the phosphor, thereby improving the effect of suppressing the mislanding of the electron beam. At the same time, the fine pitch of the apertures of the color selection mask can produce a high-definition color CRT.

In the method for manufacturing a color selection mask for a cathode ray tube according to the present invention, the time for performing isotropic etching from the emission surface side of the electron beam toward the inside is the time for performing isotropic etching from the incidence surface side. Since the length was made longer than that, over-etching could be performed on the emission surface of the metal plate below the patterned resist film.

Accordingly, the control edge of the electron beam can be formed at a position close to the incident surface of the electron beam, and the distance from the boundary edge to the emission surface of the electron beam is longer than in the conventional method of manufacturing a color selection mask. We were able to. As a result, the shield distance for geomagnetism was increased, and the effect of suppressing the mislanding of the electron beam was improved.

The method of manufacturing the cathode ray tube and the color selection mask according to the present invention as described above is characterized in that the arrangement pitch of the openings of the color selection mask is 0.25 mm or less, and that the color cathode ray tube has a high definition which is strong against geomagnetism And it is very suitable for application to its production.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a cathode ray tube as an embodiment.

FIG. 2 is a cross-sectional view of the aperture grill 21.

FIG. 3 is a diagram illustrating the function of an aperture grill 21;

FIG. 4 is a process chart of forming an aperture grill 21 (part 1);
It is.

FIG. 5 is a process chart of forming the aperture grill 21 (part 2).
It is.

FIG. 6 is a comparison diagram between the present embodiment and a conventional example.

FIG. 7 is a perspective view of a cathode ray tube.

FIG. 8 is a sectional view when the aperture grill 2 is formed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Phosphor glass panel, 2, 21 ... Aperture grill (color selection electrode; iron plate), 3 ... Electron gun, 4 ...
..Funnel, 5 ... Internal magnetic shield plate, 6
・ Spring holder, 7 ・ ・ ・ Spring, 8 ・ ・ ・ A
G frame A member, 9 ... AG frame B member, 10 ... frit seal part, 11A, 21A ...
-Incident surface, 11B, 21B ... Outgoing surface, 12A-12
C, 23A to 23C: control edge, 13, 14, 2
5, 26: resist film, 15A to 15C, 22A to
22C: slit (groove), 16: electron beam, 24: phosphor stripe, 27: filler

Claims (3)

[Claims] 1. A color selection mask having an electron gun and a plurality of apertures for allowing an electron beam emitted from the electron gun to pass therethrough, and a phosphor which is colored by the electron beam passing through the color selection mask When the thickness of the color selection mask is t and the arrangement pitch of the apertures of the color selection mask is P, the color selection mask satisfies 0.5 ≦ t / P ≦ 1.0. Wherein the thickness and the arrangement pitch are defined. 2. The color selection mask has an entrance surface and an exit surface of an electron beam, an aperture portion extending from the entrance surface of the electron beam to the exit surface, and an aperture portion extending from the exit surface of the electron beam to the entrance surface. When the boundary edge portion with the portion is a control edge that defines the irradiation width of the electron beam, the control edge is formed at a position close to the incident surface of the electron beam, and extends from the emission surface of the electron beam to the control edge. 2. The cathode ray tube according to claim 1, wherein the opening has an over-etched cross-sectional shape. 3. When the first surface of the metal plate is an electron beam incident surface and the second surface of the metal plate is an electron beam emission surface, the first surface of the metal plate is firstly arranged at a predetermined arrangement pitch. Patterning a resist film having an opening width and patterning a resist film having a second opening width at substantially the same arrangement pitch on the second surface of the metal plate; filling the entire surface of the first surface of the metal plate A step of applying an agent; a step of over-etching the metal plate with an isotropic etching solution using the resist film having the second opening width as a mask; and a step of removing the filling agent and the first opening width. Etching the metal plate with an isotropic etching solution using the resist film as a mask. Isotropic etching from the surface Applied by lengthening the time, method for producing a cathode ray tube the color selection mask from the second surface, characterized in that so as to over-etching of the metal plate.