JP2004241322A - Manufacturing method for shadow mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a focal mask type shadow mask capable of attaining stable focal performance and displaying an excellent screen. <P>SOLUTION: This manufacturing method for the shadow mask selecting an electron beam from an electron beam structure comprises a process forming a dielectric layer 103 on one main surface facing the electron beam structure of a shadow mask base material 52 having a plurality of openings 34 formed regularly, a process forming the shadow mask base material 52 in a specified shape, and a process forming a low resistor layer 110 by spraying minute droplets of ink containing conductive particles on the dielectric layer 103. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a shadow mask applied to a color cathode ray tube, and more particularly, to a method of manufacturing a focus mask type shadow mask.
[0002]
[Prior art]
One of the important characteristics of a color cathode ray tube is luminance of a screen. Various techniques have been studied to improve the brightness of a color cathode ray tube. Above all, attempts have been made to improve the luminance by a method called a focus mask (for example, see Patent Documents 1 and 2).
[0003]
Hereinafter, the principle of the focus mask will be described.
[0004]
At present, a color cathode ray tube, which is mainly used, has a shadow mask having a color selection function therein. After being deflected by the deflecting magnetic field, a part of the electron beam emitted from the electron gun assembly passes through the opening of the shadow mask and collides with the phosphor. At this time, about 20% of the electron beam emitted from the electron gun assembly passes through the opening of the shadow mask, and about 80% of the remaining electron beam only collides with the shadow mask, resulting in a brightness of the screen. Has not contributed. The focus mask aims to make a part of the electron beam colliding with such a shadow mask reach the phosphor.
[0005]
More specifically, the focus mask type shadow mask includes an electrode disposed on the surface on the electron gun structure side. A different potential from the shadow mask is applied to this electrode, and a quadrupole lens is constituted by the shadow mask and the electrode. The trajectory of the electron beam colliding with the shadow mask is changed by the quadrupole lens, and the electron beam is guided to the phosphor.
[0006]
According to Patent Literature 1, a structure is proposed in which an insulating layer is disposed on the surface of the shadow mask on the electron gun structure side, and a conductive layer is formed on the insulating layer. Further, according to Patent Document 2, a method of manufacturing such a focus mask type shadow mask is specifically disclosed.
[0007]
[Patent Document 1]
U.S. Pat. No. 4,427,918
[0008]
[Patent Document 2]
JP-A-63-62129
[0009]
[Problems to be solved by the invention]
However, in both Patent Literature 1 and Patent Literature 2, the insulating layer and the conductive layer are formed in separate steps, and the insulating layer and the conductive layer are formed in a step before press-molding the shadow mask substrate. ing. In particular, the conductive layer is easily peeled off when stress is applied to the shadow mask substrate by the press molding process.
[0010]
As described above, when the conductive layer is partially peeled, a desired electron lens cannot be formed near the opening of the shadow mask, and stable electron beam focusing performance cannot be obtained over the entire screen. For this reason, the focus performance of the electron beam is different between the portion where the desired electron lens is formed and the portion where the undesired electron lens is formed, and there is a possibility that the screen may have uneven brightness. Therefore, there arises a problem that a high-quality screen cannot be stably displayed.
[0011]
SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and has as its object to achieve a focus which is easy to manufacture, can obtain stable focus performance, and can display a high-quality screen. An object of the present invention is to provide a method of manufacturing a mask type shadow mask.
[0012]
[Means for Solving the Problems]
A method for manufacturing a shadow mask according to an embodiment of the present invention includes:
In a method of manufacturing a shadow mask for selecting an electron beam from an electron gun assembly,
Forming a dielectric layer on one principal surface of the shadow mask substrate having a plurality of regularly-perforated openings and facing the electron gun assembly;
Molding the shadow mask substrate into a predetermined shape,
Forming a low-resistance layer by ejecting fine droplets of ink containing conductive particles on the dielectric layer,
It is characterized by having.
[0013]
According to the shadow mask manufacturing method, the low-resistance layer is formed by ejecting minute droplets of ink containing conductive particles. The step of forming the low resistance layer by such a method can be performed after the shadow mask substrate is molded into a predetermined shape. In other words, when the low-resistance layer is formed by printing and coating using a method such as roller coating or screen printing, the paste-like conductive material is applied while applying stress to the shadow mask substrate, and thus is placed on a support. It is desirable that the process be performed on a flat-shaped shadow mask substrate in a sunk state. That is, it is desirable to form the low resistance layer before molding the shadow mask substrate. However, when the shadow mask substrate is molded after the formation of the low resistance layer, there is a possibility that the low resistance layer is peeled as described above.
[0014]
On the other hand, when the low-resistance layer is formed by a so-called inkjet method of ejecting minute droplets of ink containing conductive particles, the ink can be applied without applying stress to the shadow mask substrate. . Therefore, a low-resistance layer can be formed with high accuracy even on a shadow mask substrate molded into a predetermined shape. As described above, since the low-resistance layer is formed on the formed shadow mask base material, it is possible to suppress the separation of the low-resistance layer as described above. In addition, since the occurrence of defects due to the separation of the low resistance layer can be suppressed, the manufacturing yield can be improved, and the cost can be reduced.
[0015]
In a color cathode ray tube equipped with such a focus mask type shadow mask, during operation, the dielectric layer irradiated with the electron beam is negatively charged. Thereby, the dielectric layer forms an electron lens acting on the electron beam. When the electron beam passes through the opening of the shadow mask, it passes through dielectric layers provided on both sides of the opening and receives repulsive force from both sides by these dielectric layers to be focused. For this reason, it becomes possible to pass a part of the electron beam, which has collided with the shadow mask, out of the electron beam heading for the opening through the opening.
[0016]
At this time, since the peeling of the low resistance layer can be suppressed, a desired electron lens can be formed over the entire screen, and stable electron beam focusing performance can be obtained. Therefore, the amount of the electron beam passing through the aperture increases, the density of the electron beam reaching the phosphor screen can be increased, and the brightness of the entire screen can be improved. Moreover, it is possible to stably display a high-quality screen without luminance unevenness.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a method for manufacturing a shadow mask according to an embodiment of the present invention will be described in detail with reference to the drawings.
[0018]
As shown in FIG. 1, the color cathode ray tube includes a vacuum envelope 10. The vacuum envelope 10 includes a panel 1 having a skirt portion 2 on a peripheral edge and a substantially rectangular outer surface, and a funnel 4 connected to the skirt portion 2 of the panel 1. The phosphor screen 6 is arranged on the inner surface of the panel 1. The deflection yoke 7 is mounted on the outer periphery of the neck 3 to the funnel 4 and includes a horizontal deflection coil and a vertical deflection coil.
[0019]
The in-line type electron gun assembly 9 is disposed inside a cylindrical neck 3 corresponding to a small diameter portion of the funnel 4. The electron gun assembly 9 emits three electron beams 8 (B, G, R) arranged in a row in the horizontal direction X, which includes a center beam 8G passing on the same horizontal plane and a pair of side beams 8B, 8R on both sides thereof. Release in the axial direction Z. An inner shield 11 that shields an external magnetic field is disposed inside a joint between the panel 1 and the funnel 4.
[0020]
The shadow mask 12 is disposed inside the vacuum envelope 10 so as to face the phosphor screen 6, and is attached to a rectangular mask frame 14. As will be described later, the shadow mask 12 has a mask main surface 20 in which a large number of electron beam passage openings (hereinafter, referred to as openings) for color selection are formed, and a tube axial direction from the periphery of the mask main surface 20. And a skirt portion 18 extending to Z and fixed to the mask frame 14, and is formed by press molding. The shadow mask 12 is detachably supported on the panel 1 by engaging an elastic support 15 fixed to a mask frame 14 with a stud pin 17 protruding from an inner surface of the skirt portion 2.
[0021]
The vacuum envelope 10 and the shadow mask 12 include a tube axis Z extending from the center axis of the cylindrical neck 3 through the center of the panel 1, and a long axis (horizontal axis) X extending perpendicular to the tube axis Z. And a short axis (vertical axis) Y extending perpendicular to the tube axis Z and the long axis X.
[0022]
In the color cathode ray tube having the above-described configuration, the three electron beams 8B, 8G, and 8R emitted from the electron gun assembly 9 generate the deflection magnetic field generated by the deflection yoke 7, that is, the pincushion-type horizontal deflection magnetic field and the barrel-type deflection magnetic field. Is deflected in the horizontal direction X and the vertical direction Y by the non-uniform magnetic field formed by the vertical deflection magnetic field, and scans the phosphor screen 6 in the horizontal direction X and the vertical direction Y through the opening of the shadow mask 12. Thereby, a color image is displayed.
[0023]
As shown in FIG. 2, each of the phosphor screens 6 has a plurality of stripe-shaped black light absorbing members extending in the vertical direction Y of the panel 1 and arranged in parallel with a predetermined gap in the horizontal direction X. It has a layer 40 and striped three-color phosphor layers 42B, 42G, 42R provided in the gaps between the light absorbing layers 40 and extending along the vertical direction Y.
[0024]
As shown in FIGS. 1 and 3A and 3B, the shadow mask 12 is formed by press molding and has a substantially rectangular mask main surface 20 formed in a gentle dome shape, and a mask main surface. And a skirt portion 18 extending along the tube axis direction Z from the peripheral edge 21 over the entire circumference of the skirt 20. The mask main surface 20 includes a substantially rectangular perforated portion 20a in which a large number of aperture rows 19 are formed at a predetermined arrangement pitch, and a rectangular frame-shaped non-perforated portion 20b surrounding the perimeter of the perforated portion 20a. have.
[0025]
The plurality of aperture rows 19 provided in the perforated portion 20a each extend substantially parallel to the vertical direction Y and are provided substantially in parallel with a predetermined arrangement pitch in the horizontal direction X. Each of the aperture rows 19 is configured by arranging a plurality of apertures 34 in a row via bridges 32, respectively. Each of the openings 34 is formed in an elongated and substantially rectangular shape, and is formed so that the width direction is parallel to the horizontal direction X of the shadow mask 12 and the longitudinal direction is parallel to the vertical direction Y of the shadow mask. Have been. Each opening 34 is formed by a communication hole formed by connecting a large hole opened on the surface of the shadow mask 12 on the phosphor screen side and a small hole opened on the surface of the electron gun structure side to each other. I have.
[0026]
Further, the apertures 34 of one aperture row 19 are shifted by 1/2 pitch in the vertical direction Y with respect to the apertures 34 of the other adjacent aperture row 19, and are arranged in a staggered manner. . The arrangement pitch of the aperture rows 19 is set to different values in the central portion and the peripheral portion of the perforated portion 20a. In particular, the arrangement pitch gradually increases from the central portion of the perforated portion 20a toward the peripheral portion in the horizontal direction X. It is getting bigger.
[0027]
In this embodiment, the shadow mask 12 is formed of amber (Fe-36% Ni alloy) having a thickness of 0.22 mm. Further, the opening pitch in the vertical direction Y in each opening row 19 is 0.6 mm, and the arrangement pitch along the horizontal direction X of the opening row 19 is 0.75 mm in the center of the hole section 20a. The variable pitch was 0.82 mm at the periphery of the hole 20a, and increased as approaching the periphery in the horizontal direction X from the center.
[0028]
The opening size of the large hole constituting the opening 34 in the width direction was 0.46 mm at the center of the hole 20a and 0.50 mm at the periphery of the hole 20a. The opening size of the small hole constituting the opening 34 in the width direction was 0.18 mm at the center of the hole 20a and 0.20 mm at the periphery of the hole 20a. Further, when the electron beam is incident on the peripheral portion of the perforated portion 20a at a deflection angle of 46 °, the opening 34 in the peripheral portion has a shape in which the large hole is eccentric by 0.06 mm with respect to the small hole.
[0029]
On the other hand, according to this embodiment, the shadow mask 12 includes the plurality of stripe-shaped protrusions 50 provided on the surface of the perforated portion 20a on the electron gun structure side. The protrusion 50 is formed to include a dielectric layer 50A and a low-resistance layer 50B having a lower volume resistivity than the dielectric layer 50A. In this embodiment, the low resistance layer 50B is laminated on the dielectric layer 50A.
More specifically, as shown in FIGS. 4 to 6, on the surface of the perforated portion 20 a on the side of the electron gun assembly, between the adjacent hole rows 19, that is, on both sides of each hole row 19, Stripe-shaped protrusions 50 are formed, and extend substantially parallel along the vertical direction Y of the shadow mask 12.
[0030]
Each protruding portion 50 has a substantially rectangular cross section, for example, a width 50W along the horizontal direction X is about 0.25 to 0.3 mm, and a height 50H is about 0.03 to 0.05 mm. Is formed. Each protrusion 50 includes a dielectric layer 50A disposed as a lower layer, and a low resistance layer 50B disposed as an upper layer of the dielectric layer 50A.
[0031]
The low resistance layer 50B is formed to have a smaller width than the dielectric layer 50A. In this embodiment, the low-resistance layer 50B must be reliably disposed on the dielectric layer 50A after the dielectric layer 50A has been formed. It is desirable that the width of 50B be smaller than that of dielectric layer 50A. The cross-sectional shape of the protruding portion 50 is not limited to a rectangle, but may be another shape such as a substantially semicircular shape.
[0032]
In this embodiment, the dielectric layer 50A has a thickness of 0.01 to 0.03 mm. On the other hand, the low resistance layer 50B has a thickness of 0.001 to 0.01 mm, preferably 0.005 to 0.01 mm. The dielectric layer 50A has a width of about 0.3 mm. On the other hand, the low resistance layer 50B has a width of about 0.2 mm.
[0033]
The dielectric layer 50A is formed by sintering an insulating material containing glass as a main component. A preferable material is bismuth-based borosilicate glass, and at least one of lithium-based alkali borosilicate glass, lead glass, and the like may be used as long as the surface roughness, the dielectric constant, and the volume resistivity are appropriate. It is also possible to use as a main component. A dielectric layer 50A is formed by printing and applying a glass paste obtained by kneading such a glass powder with a cellulose-based binder and a solvent, followed by drying and sintering. In addition, these glasses may contain an adjusting agent such as a pigment for adjusting the surface roughness, the dielectric constant, the volume resistivity, and the like.
[0034]
In this embodiment, the dielectric layer 50A has an average surface roughness of 0.2 μm or less (preferably 0.15 μm or less), a dielectric constant of 3 or more (preferably 5 or more), In addition, the volume resistivity is 1.0E + 12 or more (preferably 5.0E + 12 or more) and 1.0E + 16Ω · cm or less.
[0035]
On the other hand, the low resistance layer 50B is formed by ejecting and sintering fine droplets of ink in which a metallic material, that is, conductive particles are dispersed in an organic solvent. A preferred material is an ink containing an ultrafine silver sintered body. That is, the low-resistance layer 50B according to this embodiment is formed by a so-called ink-jet method of controlling ejection of fine ink droplets by a pressure control method or an electric field control method. For this reason, it is desirable to use an ink in which ultrafine conductive particles having a particle size of 0.1 μm or less are dispersed in an organic solvent having appropriate viscosity. Such an ink can remove the organic solvent by being baked, and has excellent sinterability of the ultrafine particles.
[0036]
The low resistivity layer 50B has a volume resistivity of, for example, less than 1.0E + 3. By setting the width of the low-resistance layer 50B appropriately with respect to the width of the dielectric layer 50A, the exposed area of the dielectric layer 50A can be changed, and the volume resistivity and the dielectric constant of the dielectric layer 50A can be changed. Is determined in consideration of
[0037]
The average surface roughness of the dielectric layer 50A was measured using a surface roughness meter SE-30H manufactured by Kosaka Seisakusho under the condition of a cutoff of 0.08 mm. In addition, the dielectric constant and the volume resistivity were measured based on JIS C2141 “Test method for ceramic materials for electrical insulation”.
[0038]
It is desirable that the positions of the projections 50 with respect to the aperture row 19 be different between the central portion of the perforated portion 20a and the peripheral portion of the perforated portion 20a. That is, in the central portion of the perforated portion 20a, each protruding portion 50 is disposed substantially at the center between two adjacent rows of apertures 19. Since the electron beam 8 is incident on the surface of the shadow mask 12 almost perpendicularly at the center of the perforated portion 20a, the projecting portions 50 located on both sides of each opening 34 are It is desirable to be provided symmetrically.
[0039]
In addition, the protruding portion 50 provided in the peripheral portion of the perforated portion 20a is disposed closer to the opening row 19 than the protruding portion 50 provided in the center of the perforated portion 20a. ing. That is, in the peripheral portion, the protruding portion 50 provided between the two adjacent rows of apertures 19 is arranged close to the aperture row on the center side of the mask. At the periphery of the perforated portion 20a, the electron beam 8 is incident at a predetermined angle with respect to the normal to the surface of the shadow mask 12. For this reason, by arranging the projections 50 located on both sides of each opening 34 on the center side, respectively, the distance between each projection 50 and the electron beam 8 passing through the opening 34 is made substantially equal. be able to.
[0040]
That is, by making the distance between the electron beam 8 passing through the opening 34 and each of the protrusions 50 substantially the same over the entire area of the shadow mask 12, the protrusions 50 provided on both sides of the electron beam 8 Acts almost uniformly on the electron beam 8. Thus, it is possible to prevent the trajectory of the electron beam 8 from being shifted undesirably, and it is possible to obtain good focus characteristics in the entire screen area.
[0041]
Such an effect can be obtained by changing the arrangement position of the protrusion 50 including the dielectric layer 50A with respect to the aperture row 19 between the central portion and the peripheral portion of the perforated portion of the shadow mask. The same effect can be obtained by adjusting the width and height of the protruding portion 50 between the central portion and the peripheral portion of the hole 20a.
[0042]
According to the color cathode ray tube configured as described above, by applying a voltage having a difference of 50 to 1000 V with respect to the voltage applied to the shadow mask, the vicinity of the opening 34 of the shadow mask 12 is efficiently provided. A stable quadrupole lens is formed.
[0043]
As shown in FIG. 4 and FIG. 6, this quadrupole lens transmits an electron beam 8 that passes between two adjacent dielectric layers 50A and travels toward the opening 34 so that the width direction of the opening 34 is smaller than the actual opening diameter. In addition to converging thinly, the lens has a lens function such that the longitudinal direction of the aperture 34 diverges longer than the actual aperture diameter. As a result, the electron beam 8 that has passed through the opening 34 of the shadow mask 12 is focused on a vertically long shape.
[0044]
By focusing the electron beam 8 in a vertically long shape in this manner, a part of the electron beam that has collided with the shadow mask 12 can be guided to the phosphor screen 6 through the opening 34. In the longitudinal direction of the opening 34, that is, in the vertical direction Y of the shadow mask 12, the phosphor layer portion which has been shadowed by the bridge 32 of the shadow mask 12 emits light. Spot density can be increased. As a result, the luminous efficiency of the phosphor layer can be improved, and the luminance of the screen can be improved.
[0045]
In experiments conducted by the inventors of the present application, when the color cathode ray tube was operated under the above-described conditions, it was possible to achieve about 20% improvement in luminance as compared with the conventional case.
[0046]
Next, a method of manufacturing the shadow mask in the method of manufacturing the color cathode ray tube configured as described above will be described.
[0047]
First, as shown in FIG. 7, a rectangular plate-shaped shadow mask base material (flat mask) 52 such as an amber material is prepared, and a large number of openings 34 are regularly formed in a region to be the perforated portion 20a.
[0048]
Subsequently, a dielectric layer 50A is formed on one main surface of the shadow mask substrate 52 facing the electron gun structure. That is, the dielectric layer forming step includes a step of printing and applying a paste containing an insulating material by using a screen printing method or the like, and a step of firing the printed and applied paste. Alternatively, the dielectric layer forming step includes a step of transferring the dielectric layer of the transfer film by a photolithography method using a transfer film having at least the dielectric layer, and a step of firing the transferred dielectric layer. You may go out.
[0049]
In this embodiment, a case will be described in which the dielectric layer 50A is formed on the shadow mask 12 using the transfer film 100 on which the dielectric layer 103 is laminated. That is, as shown in FIG. 8A, the transfer film 100 on which at least the dielectric layer 103 is laminated is placed on one main surface of the shadow mask substrate 52 facing the electron gun assembly.
[0050]
That is, the transfer film 100 is configured by laminating a dielectric layer 103 on a base film 101 as shown in FIG. As described above, the dielectric layer 103 is made of an insulating material mainly containing bismuth-based borosilicate glass, and further contains a photosensitive resin. The photosensitive resin contained in the dielectric layer 103 undergoes a cross-linking reaction when irradiated with light having a predetermined wavelength, and becomes insoluble in a predetermined developing solution. The dielectric layer 103 has light transmittance, that is, has a predetermined transmittance for light of a predetermined wavelength for exposure. In this transfer film 100, a release agent may be disposed between the base film 101 and the dielectric layer 103, an adhesive may be disposed on the surface of the dielectric layer 103, or Alternatively, a protective film may be provided on the surface of the dielectric layer 103.
[0051]
After the transfer film 100 having such a structure is disposed with the dielectric layer 103 facing the shadow mask base material 52, the transfer film 100 is pressed or used in combination with pressurization and overheating. Glued on the surface. Thus, the dielectric layer 103 of the transfer film 100 and the base film 101 are laminated on the shadow mask substrate 52 in this order.
[0052]
Subsequently, as shown in FIG. 8B, the transfer film 100 is exposed through a photomask PM having a predetermined pattern. In this exposure step, at least the dielectric layer 103 of the transfer film 100 may be exposed according to a predetermined pattern. In other words, when the base film 101 has light transmittance, that is, when the base film 101 has a predetermined transmittance for light of a predetermined wavelength for exposure, the transfer film provided with the base film 101 is provided. By exposing 100, the dielectric layer 103 is exposed. When the base film 101 has a light-shielding property, the base film 101 is removed before the exposure step, and the dielectric layer 103 is directly exposed. Thus, the base film 101 of the transfer film 100 is removed before or after the exposure step.
[0053]
Note that the photomask PM applied in this exposure step has a stripe-shaped opening pattern corresponding to both sides of each of the aperture rows 19 formed in the shadow mask substrate 52. That is, in a state where the photomask PM is positioned on the transfer film 100, the aperture row including the apertures 34 of the shadow mask substrate 52 is shielded from light, and the transfer film 100 between the aperture rows is exposed in a stripe shape. Will be done.
[0054]
Subsequently, as shown in FIG. 8C, the exposed transfer film 100 is developed under a predetermined condition using a predetermined developer. In this developing step, the dielectric layer 103 of the transfer film 100 is selectively removed. That is, since the dielectric layer 103 of the transfer film 100 employed in this embodiment contains a so-called negative type photosensitive resin, the unexposed dielectric layer 103 is removed. That is, the dielectric layer 103 located on the aperture row including the aperture 34 of the shadow mask base material 52 is removed, and the dielectric layer 103 located between the aperture rows remains in a stripe shape.
[0055]
After transferring the dielectric layer 103 of the transfer film 100 onto the shadow mask substrate 52 by a series of photolithography methods, a firing step of the dielectric layer 103 is performed. That is, the dielectric layer 103 remaining on the shadow mask substrate 52 is fired at a predetermined temperature. As a result, the dielectric layer 50A is formed on the shadow mask substrate 52.
[0056]
Subsequently, as shown in FIG. 8D, the shadow mask base material 52 is mounted on a press die and press-molded under predetermined conditions. Thus, the shadow mask 12 having the mask main surface 20 and the skirt portion 18 having a desired shape is formed. Note that the firing step of the dielectric layer 103 may be performed after the molding step of the shadow mask substrate 52.
[0057]
Subsequently, as shown in FIG. 8E, fine particles of ink containing conductive particles are ejected onto the dielectric layer 103 to form the low-resistance layer 110. That is, the low resistance layer forming step includes a step of ejecting ink on the dielectric layer 103 with high accuracy by a so-called inkjet method, and a step of firing the ink on the dielectric layer 103. Note that the firing step of the low-resistance layer 110 may be performed simultaneously with the firing step of the dielectric layer 103 at this timing. As a result, a protrusion 50 including the dielectric layer 50A and the low resistance layer 50B is formed.
[0058]
Through the above steps, a shadow mask 12 having a predetermined shape and having the stripe-shaped protrusions 50 on the surface on the electron gun structure side is obtained.
[0059]
According to such a manufacturing method, the dielectric layer 50A having a predetermined pattern is formed on one main surface of the shadow mask base material 52, and the shadow mask base material 52 is formed into a predetermined shape. Form 50B. Since the low-resistance layer 50B is formed by such a method, the low-resistance layer 50B can be formed on the shadow mask substrate 52 with high accuracy. Further, since the low-resistance layer 50B is formed on the formed shadow mask substrate 52, it is possible to suppress undesired peeling of the low-resistance layer 50B. In addition, since the occurrence of defects due to the separation of the low resistance layer 50B can be suppressed, the manufacturing yield can be improved, and the cost can be reduced.
[0060]
Further, according to the color cathode ray tube equipped with the shadow mask 12 manufactured as described above, since the peeling of the low resistance layer can be suppressed, a desired electron lens can be formed over the entire screen, and stable. The focus performance of the focused electron beam can be obtained. Therefore, the amount of the electron beam passing through the opening 34 of the shadow mask 12 increases, the density of the electron beam reaching the phosphor screen 6 can be increased, and the brightness of the entire screen can be improved. Moreover, it is possible to stably display a high-quality screen without luminance unevenness.
[0061]
Next, a method for manufacturing another shadow mask will be described. Also in this embodiment, the step of forming the dielectric layer 50A may be performed by a screen printing method as in the above-described embodiment, or at least using the transfer film 100 on which the dielectric layer 103 is laminated. May go. Here, an example in which the transfer film 100 is used will be described, but the structure of the transfer film applied to the above-described embodiment is slightly different.
[0062]
That is, as shown in FIG. 10, the transfer film 100 has a photoresist layer 104 made of a photosensitive resin on a base film 101, and a dielectric layer 103 is sequentially laminated on the photoresist layer 104. It is configured. As in the above-described embodiment, the dielectric layer 103 is formed of an insulating material mainly containing bismuth-based borosilicate glass. Further, in the case of the transfer film 100 having such a structure, it is not necessary to make the dielectric layer 103 contain a photosensitive resin. The photoresist layer 104 causes a cross-linking reaction when irradiated with light having a predetermined wavelength, and is insoluble in a predetermined developing solution. In this transfer film 100, a release agent may be disposed between the base film 101 and the photoresist layer 104, an adhesive may be disposed on the surface of the dielectric layer 103, or Alternatively, a protective film may be provided on the surface of the dielectric layer 103.
[0063]
In the method of manufacturing a shadow mask according to this embodiment, first, a rectangular plate-shaped shadow mask base material (flat mask) 52 such as an amber material is prepared, and a large number of holes are regularly formed in a region to be the perforated portion 20a. Drill 34.
[0064]
Subsequently, a dielectric layer 50A is formed on one surface of the shadow mask substrate 52 by a series of photolithography methods. That is, as shown in FIG. 11A, the transfer film 100 on which at least the dielectric layer 103 and the photoresist layer 104 are laminated is provided on one main surface of the shadow mask substrate 52 facing the electron gun assembly. I do. Thus, the dielectric layer 103, the photoresist layer 104, and the base film 101 of the transfer film 100 are laminated on the shadow mask substrate 52 in this order.
[0065]
Subsequently, as shown in FIG. 11B, the transfer film 100 is exposed through a photomask PM having a predetermined pattern. In this exposure step, at least the photoresist layer 104 of the transfer film 100 may be exposed in accordance with a predetermined pattern. That is, when the base film 101 has light transmittance, the photoresist layer 104 is exposed by exposing the transfer film 100 on which the base film 101 is provided. When the base film 101 has a light-shielding property, the base film 101 is removed before the exposure step, and the photoresist layer 104 is directly exposed. Note that the photomask PM applied in this exposure step has a stripe-shaped opening pattern corresponding to both sides of each of the aperture rows 19 formed in the shadow mask substrate 52.
[0066]
Subsequently, as shown in FIG. 11C, the exposed transfer film 100 is developed under a predetermined condition using a predetermined developer. In this developing step, the photoresist layer 104 of the transfer film 100 is selectively removed. That is, since the photoresist layer 104 of the transfer film 100 employed in this embodiment is a so-called negative type photosensitive resin, the unexposed photoresist layer 104 is removed. That is, the photoresist layer 104 located on the aperture row including the aperture 34 of the shadow mask substrate 52 is removed, and the photoresist layer 104 located between the aperture rows remains in a stripe shape.
[0067]
Subsequently, as shown in FIG. 11D, the portions where the photoresist layer 104 is removed and the dielectric layer 103 is exposed are removed by etching under predetermined conditions. In this etching step, the exposed dielectric layer 103 is removed. As a result, the dielectric layer 103 located on the aperture row including the apertures 34 of the shadow mask base material 52 is removed. Thereafter, by removing the remaining photoresist layer 104, the dielectric layer 103 located between the aperture rows remains in a stripe shape.
[0068]
In this embodiment, the developing step and the etching step are performed in separate processes. However, by selecting an appropriate developing solution and setting appropriate developing conditions, the developing process of the photoresist layer 104 and the dielectric process are performed. The etching of the layer 103 can be performed simultaneously and collectively.
[0069]
After transferring the dielectric layer 103 of the transfer film 100 onto the shadow mask substrate 52 by a series of photolithography methods, a firing step of the dielectric layer 103 is performed. That is, the dielectric layer 103 remaining on the shadow mask substrate 52 is fired at a predetermined temperature. As a result, the dielectric layer 50A is formed on the shadow mask substrate 52.
[0070]
Subsequently, as shown in FIG. 11E, the shadow mask base material 52 is mounted on a press die and press-molded under predetermined conditions. Thus, the shadow mask 12 having the mask main surface 20 and the skirt portion 18 having a desired shape is formed. Note that the firing step of the dielectric layer 103 may be performed after the molding step of the shadow mask substrate 52.
[0071]
Subsequently, as shown in FIG. 11F, fine particles of ink containing conductive particles are ejected onto the dielectric layer 103 to form the low-resistance layer 110. That is, the low resistance layer forming step includes a step of ejecting ink on the dielectric layer 103 with high accuracy by a so-called inkjet method, and a step of firing the ink on the dielectric layer 103. Note that the firing step of the low-resistance layer 110 may be performed simultaneously with the firing step of the dielectric layer 103 at this timing. As a result, a protrusion 50 including the dielectric layer 50A and the low resistance layer 50B is formed.
[0072]
Through the above steps, a shadow mask 12 having a predetermined shape and having the stripe-shaped protrusions 50 on the surface on the electron gun structure side is obtained. In such an embodiment, the same effects as described above can be obtained.
[0073]
The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, the openings formed in the shadow mask may be not only rectangular but also circular, and the phosphor layer on the phosphor screen side may be not only stripe but also dot.
[0074]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a method of manufacturing a focus mask type shadow mask capable of obtaining stable focus performance and displaying a high-quality screen.
[Brief description of the drawings]
FIG. 1 is a horizontal sectional view schematically showing a structure of a color cathode ray tube according to an embodiment of the present invention.
FIG. 2 is an enlarged plan view showing a part of a phosphor screen in the color cathode ray tube shown in FIG. 1;
3A is a perspective view schematically showing a structure of a shadow mask in the color cathode ray tube shown in FIG. 1, and FIG. 3B is an enlarged view of a part of the shadow mask. FIG.
FIG. 4 is a diagram schematically showing a relationship between a shadow mask, a phosphor screen, and an electron beam.
FIG. 5 is a perspective view schematically showing the structure of the surface of the shadow mask on which the projections are formed on the electron gun assembly side.
FIG. 6 is a diagram schematically illustrating a focus state of an electron beam passing through a central portion of a perforated portion of a shadow mask.
FIG. 7 is a plan view showing a shadow mask base material applied to the shadow mask manufacturing method.
FIGS. 8A to 8E are views for explaining a method of manufacturing a shadow mask according to an embodiment of the present invention.
FIG. 9 is a sectional view schematically showing a structure of a transfer film applied to the method of manufacturing the shadow mask shown in FIG. 8;
FIG. 10 is a cross-sectional view schematically showing a structure of a transfer film applied to another embodiment.
FIGS. 11A to 11F are diagrams for explaining a method of manufacturing a shadow mask according to another embodiment. FIGS.
[Explanation of symbols]
6: phosphor screen, 9: electron gun assembly, 10: vacuum envelope, 12: shadow mask, 19: aperture row, 20: mask main surface, 20a: aperture, 34: aperture, 42R, 42G , 42B phosphor layer, 50 projecting part, 50A dielectric layer, 50B low resistance layer, 52 mask base material, 100 transfer film, 103 dielectric layer, 110 low resistance layer

Claims (12)

In a method of manufacturing a shadow mask for selecting an electron beam from an electron gun assembly,
Forming a dielectric layer on one principal surface of the shadow mask substrate having a plurality of regularly-perforated openings and facing the electron gun assembly;
Molding the shadow mask substrate into a predetermined shape,
Forming a low-resistance layer by ejecting fine droplets of ink containing conductive particles on the dielectric layer,
A method for manufacturing a shadow mask, comprising: 2. The method according to claim 1, wherein the step of forming the low-resistance layer includes a step of baking the ink jetted onto the dielectric layer. 2. The method of claim 1, wherein the step of forming the dielectric layer includes a step of printing and applying a paste containing an insulating material, and a step of baking the printed and applied paste. The step of forming the dielectric layer,
A step of providing a transfer film having at least a dielectric layer on one main surface of the shadow mask substrate,
Exposing the transfer film through a photomask of a predetermined pattern,
Developing the transfer film,
Baking the dielectric layer remaining on the shadow mask substrate,
The method for manufacturing a shadow mask according to claim 1, comprising: The method according to claim 4, wherein the transfer film is adhered onto the shadow mask substrate by pressing or by using both pressure and heating. The method according to claim 4, wherein the dielectric layer of the transfer film contains a photosensitive resin. 5. The method of claim 4, wherein the transfer film is formed by laminating the dielectric layer on a base film. The method according to claim 1, wherein the low resistance layer and the dielectric layer are formed in a stripe shape around an opening in the shadow mask substrate. The said low resistance layer and the said dielectric material layer were arrange | positioned in parallel with the aperture row which consists of several apertures arranged in the minor axis direction of the said shadow mask base material, The Claim 1 characterized by the above-mentioned. Manufacturing method of shadow mask. The method of claim 1, wherein the low resistance layer is smaller than a width of the dielectric layer. 2. The method according to claim 1, wherein the dielectric layer is formed of an insulating material containing bismuth-based borosilicate glass as a main component. The method according to claim 1, wherein the low-resistance layer contains a sintered body of ultrafine silver particles.

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