JP2005063915A - Manufacturing method of shadow mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a focus mask type shadow mask in which the reduction of manufacturing costs is realized, and manufacturing yield can be improved, and further, stable focus performance can be obtained. <P>SOLUTION: The manufacturing method of a shadow mask for selecting electron beams from an electron gun structure comprises: a process of arranging a transfer film 100 formed by laminating at least a low resistance layer 102 and a dielectric layer 103 on one principal face opposed to the electron gun structure of a shadow mask substrate 52 having a plurality of apertures 34 opened regularly; a process of exposing the transfer film 100 through a photo mask PM having a prescribed pattern, a process of developing the transfer film 100; and a process of baking the low resistance layer 102 and the dielectric layer 103 remaining on the shadow mask substrate 52. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a shadow mask applied to a color cathode ray tube, and more particularly to a method for manufacturing a focus mask type shadow mask.

  One important characteristic of a color cathode ray tube is the brightness of the screen. Various techniques have been studied in order to improve the luminance of the color cathode ray tube. In particular, attempts have been made to improve luminance by a method called a focus mask (see, for example, Patent Document 1 and Patent Document 2).

  Hereinafter, the principle of the focus mask will be described.

  A color cathode ray tube which is currently mainstream has a shadow mask having a color selection function therein. After the electron beam emitted from the electron gun assembly is deflected by the deflection magnetic field, a part of the electron beam passes through the aperture of the shadow mask and collides with the phosphor. At this time, of the electron beam emitted from the electron gun structure, about 20% of the total electron beam passes through the aperture of the shadow mask, and the remaining about 80% only hits the shadow mask. Does not contribute. The focus mask is intended to cause a part of the electron beam that collides with the shadow mask to reach the phosphor.

  More specifically, the focus mask type shadow mask includes an electrode disposed on the surface of the electron gun assembly side. A potential different from that of the shadow mask is applied to this electrode, and a quadrupole lens is constituted by the shadow mask and the electrode. This quadrupole lens changes the trajectory of the electron beam that collides with the shadow mask, and guides the electron beam to the phosphor.

According to Patent Document 1, a structure is proposed in which an insulating layer is disposed on the surface of the shadow mask on the electron gun assembly 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.
U.S. Pat. No. 4,427,918 JP-A 63-62129

  However, Patent Document 1 discloses that after forming an insulating layer, the conductive layer is formed by a method such as roller coating or vacuum deposition. As described above, when the insulating layer and the conductive layer are formed in separate steps, there arises a problem that not only the manufacturing cost increases as the number of manufacturing steps increases, but also the manufacturing time increases and the yield decreases.

  Patent Document 2 discloses a method in which, after an insulating layer is formed, a transfer film having a conductive thin film is adhered on the insulating layer, and only the conductive thin film on the insulating layer is left. Even in such a method, as described above, since the insulating layer and the conductive thin film are formed in separate steps, the same problem occurs. In the structure as disclosed in Patent Document 2, the width of the conductive thin film is smaller than that of the insulating layer, and the peripheral portion of the insulating layer (near the opening of the shadow mask) is exposed. Thus, if the exposed insulating layer is present on the electron gun assembly side, it becomes difficult to control the charge amount in this portion. For this reason, a complicated electron lens is formed in the vicinity of the aperture of the shadow mask, and there arises a problem that the focusing performance of the electron beam becomes unstable.

  The present invention has been made in view of the above-described problems, and has as its object the focus mask type shadow mask capable of reducing the manufacturing cost and improving the manufacturing yield and obtaining a stable focusing performance. It is in providing the manufacturing method of.

A method of manufacturing a shadow mask according to an aspect of the present invention is as follows.
An envelope having a panel having a phosphor screen disposed on the inner surface, an electron gun disposed in the envelope and emitting an electron beam toward the phosphor screen, and facing the phosphor screen And a shadow mask manufacturing method applied to a color cathode ray tube including a shadow mask having a plurality of apertures for selecting an electron beam emitted from the electron gun.
Providing a transfer film in which at least a dielectric layer and a low resistance layer are laminated on one main surface facing the electron gun assembly of a shadow mask base material having a plurality of regularly perforated holes;
Exposing the transfer film through a photomask having a predetermined pattern;
Developing the transfer film;
Firing the dielectric layer and the low resistance layer remaining on the shadow mask substrate;
It is provided with.

  According to this shadow mask manufacturing method, a transfer film in which a dielectric layer and a low-resistance layer are laminated is provided on one main surface of a shadow mask base material, and is developed after being exposed through a predetermined photomask. The dielectric layer and the low resistance layer having a predetermined pattern can be collectively formed on the shadow mask substrate. Accordingly, the number of manufacturing steps can be reduced, and the manufacturing time can be shortened because the process is simpler than the conventional film forming step. As a result, the manufacturing cost can be reduced and the manufacturing yield can be improved.

  The dielectric layer and the low resistance layer are formed by a single photolithography process through the same photomask. For this reason, the dielectric layer and the low resistance layer have substantially the same width. Therefore, the peripheral portion of the dielectric layer is not exposed from the low resistance layer, and unwanted charging of the dielectric layer can be suppressed. Thereby, the focusing performance of the electron beam can be maintained in a stable state. Further, by adopting such a photolithography process, it is possible to form a high-precision dielectric layer and a low-resistance layer even for a high-definition shadow mask with a fine aperture pitch.

  In a color cathode ray tube equipped with such a focus mask type shadow mask, the dielectric layer irradiated with the electron beam is negatively charged during operation. As a result, the dielectric layer forms an electron lens that acts on the electron beam. When the electron beam passes through the aperture of the shadow mask, it passes through the dielectric layers provided on both sides of the aperture, and is focused by receiving a repulsive force from both sides by these dielectric layers. For this reason, it is possible to pass a part of the electron beam that has collided with the shadow mask out of the electron beam toward the opening. Accordingly, the amount of electron beam passing through the aperture is increased, the density of the electron beam reaching the phosphor screen is increased, and the screen brightness can be improved.

  According to the present invention, it is possible to provide a method for manufacturing a focus mask type shadow mask that can reduce the manufacturing cost, improve the manufacturing yield, and obtain a stable focusing performance.

  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.

  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 the periphery 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 disposed on the inner surface of the panel 1. The deflection yoke 7 is mounted on the outer periphery from the neck 3 to the funnel 4 and includes a horizontal deflection coil and a vertical deflection coil.

  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. This electron gun assembly 9 is a tube of three electron beams 8 (B, G, R) arranged in a line in the horizontal direction X, which consists of a center beam 8G passing through 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 coupling portion between the panel 1 and the funnel 4.

  The shadow mask 12 is disposed in 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 includes a mask main surface 20 on which a large number of electron beam passage apertures (hereinafter referred to as apertures) for color selection are formed, and the periphery of the mask main surface 20 in the tube axis direction. A skirt portion 18 extending to Z and fixed to the mask frame 14, and formed by press molding. The shadow mask 12 is detachably supported on the panel 1 by engaging an elastic support 15 fixed to the mask frame 14 with a stud pin 17 protruding from the inner surface of the skirt portion 2.

  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.

  In the color cathode ray tube configured as described above, the three electron beams 8B, 8G, and 8R emitted from the electron gun assembly 9 are deflected by the deflection yoke 7, that is, a pin cushion type horizontal deflection magnetic field and a barrel type. Are 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 the phosphor screen 6 is scanned in the horizontal direction X and the vertical direction Y through the aperture of the shadow mask 12. Thereby, a color image is displayed.

  As shown in FIG. 2, each of the phosphor screens 6 extends along the vertical direction Y of the panel 1 and absorbs a plurality of stripes of black light arranged in parallel with a predetermined gap in the horizontal direction X. And the stripe-shaped three-color phosphor layers 42B, 42G, and 42R provided in the gaps between the light absorption layers 40 and extending along the vertical direction Y, respectively.

  As shown in FIGS. 1 and 3 (a) and 3 (b), the shadow mask 12 is formed by press molding and has a generally rectangular mask main surface 20 formed into a gentle dome shape, and a mask main surface. The skirt part 18 extended from the peripheral edge 21 along the pipe-axis direction Z over the perimeter of 20 is integrally provided. 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 perforated portion 20a. have.

  The plurality of aperture rows 19 provided in the perforated portion 20a extend substantially in parallel with the vertical direction Y and are provided in parallel in the horizontal direction X at a predetermined arrangement pitch. Further, each aperture row 19 is configured by arranging a plurality of apertures 34 in a row via bridges 32. Each opening 34 is formed in an elongated and substantially rectangular shape so that its width direction is parallel to the horizontal direction X of the shadow mask 12 and its longitudinal direction is parallel to the vertical direction Y of the shadow mask. Has been. Each opening 34 is constituted by a communication hole in which 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 on the electron gun assembly side communicate with each other. Yes.

  Furthermore, the apertures 34 of one aperture row 19 are located with a 1/2 pitch shift in the vertical direction Y with respect to the apertures 34 of other adjacent aperture rows 19 and are arranged in a so-called staggered shape. . The arrangement pitch of the aperture rows 19 is set to a different value between the central portion and the peripheral portion of the perforated portion 20a, and in particular, gradually from the central portion of the perforated portion 20a toward the peripheral portion in the horizontal direction X. Is getting bigger.

  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 portion of the perforated portion 20a. The variable pitch was 0.82 mm at the periphery of the hole 20a and increased from the center toward the periphery in the horizontal direction X.

  Moreover, the opening dimension of the width direction of the large hole which comprises the opening 34 was 0.46 mm in the center part of the perforated part 20a, and was 0.50 mm in the peripheral part of the perforated part 20a. Moreover, the opening dimension of the width direction of the small hole which comprises the opening 34 was 0.18 mm in the center part of the perforated part 20a, and was 0.20 mm in the peripheral part of the perforated part 20a. Further, when the electron beam is incident on the peripheral portion of the perforated portion 20a with 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.

On the other hand, according to this embodiment, the shadow mask 12 includes a plurality of stripe-shaped protrusions 50 provided on the surface of the perforated part 20a on the electron gun assembly side. The protrusion 50 includes a dielectric layer 50A and a low resistance layer (charge transfer layer) 50B having a volume resistivity lower than that of the dielectric layer 50A. In this embodiment, the low resistance layer 50B is stacked on the dielectric layer 50A.
More specifically, as shown in FIGS. 4 to 6, on the surface of the perforated portion 20a on the electron gun assembly side, between the adjacent aperture rows 19, that is, on both sides of each aperture row 19, respectively. Striped protrusions 50 are formed and extend substantially in parallel along the vertical direction Y of the shadow mask 12.

  Each protrusion 50 has a substantially rectangular cross section, for example, the width 50W along the horizontal direction X is about 0.25 to 0.3 mm, and the height 50H is about 0.03 to 0.05 mm. Is formed. Each protrusion 50 includes a dielectric layer 50A disposed in a lower layer and a low resistance layer 50B disposed in an upper layer of the dielectric layer 50A. The low resistance layer 50B is formed to have the same width as the dielectric layer 50A.

  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 and the low resistance layer 50B have a width of about 0.3 mm.

  The dielectric layer 50A is formed by sintering an insulating material mainly composed of glass. A suitable material is bismuth-based borosilicate glass. If the surface roughness, dielectric constant, volume resistivity, etc. are appropriate, at least one of lithium-based alkali borosilicate glass, lead glass, etc. is also used. It can also be used as a main component. In addition, these glasses may contain adjusting agents such as pigments for adjusting the surface roughness, dielectric constant, volume resistivity, and the like.

  In this embodiment, the dielectric layer 50A has an average surface roughness of 0.2 μm or less (preferably 0.15 μm or less), and a dielectric constant of 3 or more (preferably 5 or more). Moreover, the volume resistivity is 1.0E + 12 or more (preferably 5.0E + 12 or more) 1.0E + 16 Ω · cm or less.

  On the other hand, the low-resistance layer 50B is formed by sintering a metallic material, that is, conductive glass containing a conductive substance. A suitable material is lead borosilicate glass containing silver. In addition to this, a conversion product of metal alkoxide or the like can be used. This low resistance layer 50B has a volume resistivity of, for example, less than 1.0E + 12.

  The average surface roughness of the dielectric layer 50A was measured with a surface roughness meter SE-30H manufactured by Kosaka Seisakusho under the condition of a cutoff of 0.08 mm. The dielectric constant and volume resistivity were measured based on JIS C2141 “Test Method for Ceramic Material for Electrical Insulation”.

  It is desirable that the arrangement positions of the protruding portions 50 with respect to the aperture row 19 are different between the central portion of the perforated portion 20a and the peripheral portion of the perforated portion 20a. That is, in the central part of the perforated part 20a, each projecting part 50 is disposed substantially at the center between the two adjacent aperture arrays 19. At the central portion of the perforated portion 20 a, the electron beam 8 is incident substantially perpendicular to the surface of the shadow mask 12, so that the protruding portions 50 located on both sides of each aperture 34 are in contact with the aperture 34. It is desirable to provide symmetry.

  Further, the projecting portion 50 provided in the peripheral portion of the perforated portion 20a is disposed closer to the opening row 19 than the central portion than the projecting portion 50 provided in the central portion of the perforated portion 20a. ing. That is, in the peripheral portion, the protruding portion 50 provided between two adjacent aperture rows 19 is arranged close to the aperture row on the mask center side. At the peripheral portion of the perforated portion 20a, the electron beam 8 is incident at a predetermined angle with respect to the normal of the surface of the shadow mask 12. For this reason, the protrusions 50 located on both sides of each opening 34 are arranged on the center side, so that the distance between each protrusion 50 and the electron beam 8 passing through the opening 34 is substantially the same. be able to.

  That is, in the entire region of the shadow mask 12, by making the distance between the electron beam 8 passing through the aperture 34 and each protrusion 50 substantially the same, the protrusions 50 provided on both sides of the electron beam 8 are It acts on the electron beam 8 substantially equally. Thereby, it is possible to prevent the trajectory of the electron beam 8 from being undesirably shifted, and it is possible to obtain good focus characteristics in the entire screen area.

  Such an effect can be obtained by changing the arrangement position of the protruding portion 50 including the dielectric layer 50A with respect to the opening 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, height, or dielectric constant of the protruding portion 50 between the central portion and the peripheral portion of the hole 20a.

  According to the color cathode ray tube configured as described above, as shown in FIG. 6, a part of the electron beam 8 emitted from the electron gun assembly collides with the dielectric layer 50A of the projecting portion 50 at the beginning of operation. Each dielectric layer 50A is negatively charged. When the dielectric layer 50A is charged, a potential difference is generated between the shadow mask 12 and the dielectric layer 50A. A quadrupole lens as an electron lens is formed by this potential difference, the dielectric layer 50 </ b> A, and the opening 34 of the shadow mask 12.

  As shown in FIGS. 4 and 6, this quadrupole lens is configured so that the electron beam 8 traveling between two adjacent dielectric layers 50A toward the opening 34 is smaller than the actual opening diameter in the width direction of the opening 34. In addition, the lens function is such that the aperture 34 is diverged and the longitudinal direction of the aperture 34 is longer than the actual aperture diameter. As a result, the electron beam 8 that has passed through the aperture 34 of the shadow mask 12 is focused in a vertically long shape.

  Thus, by focusing the electron beam 8 in a vertically long shape, a part of the electron beam colliding 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 shadowed by the bridge 32 of the shadow mask 12 is caused to emit light, and in the horizontal direction X, the beam The spot density can be increased. Thereby, the luminous efficiency of the phosphor layer can be improved, and the brightness of the screen can be improved.

  In the experiment 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 a brightness improvement of about 20% compared to the conventional case.

  Further, the projecting portion 50 includes a dielectric layer 50A and a low resistance layer 50B. Therefore, the charge amount of the dielectric layer 50A, that is, the acting force on the electron beam can be adjusted, and the focus state of the electron beam can be easily controlled. That is, the electric charges charged in the dielectric layer 50A by irradiating the projecting portion 50 with the electron beam move through the low resistance layer 50B. This makes it possible to equalize the amount of charge charged in the protrusions 50 as compared with a structure in which the low resistance layer 50B is not provided. In addition, since the charges charged in the projecting portions 50 are quickly eliminated through the low resistance layer 50B, it is possible to reduce the occurrence of afterimages.

  Further, the protruding portion 50 is configured by disposing a dielectric layer 50A on a metal mask base material and further disposing a low resistance layer 50B on the dielectric layer 50A. That is, the protrusion 50 is formed in a sandwich structure in which a dielectric layer 50A charged with electric charges is sandwiched between a mask substrate having a relatively low resistance and the low resistance layer 50B. Thereby, the charge charged on the lower layer side (mask base material side) of the dielectric layer 50A and the charge charged on the upper layer side (low resistance layer side) can be quickly moved. That is, it is possible to equalize the amount of charge charged in the protruding portion 50 and quickly remove the charge.

  Next, a method for manufacturing a shadow mask in the method for manufacturing a color cathode ray tube configured as described above will be described. In this embodiment, a manufacturing method for forming the dielectric layer 50A and the low resistance layer 50B on the shadow mask 12 at the same time using the transfer film in which the dielectric layer and the low resistance layer are laminated will be described.

  First, as shown in FIG. 7, a rectangular plate-shaped shadow mask base material 52 such as an amber material is prepared, and a large number of apertures 34 are regularly drilled in a region to be the perforated portion 20a. Press molding.

  Subsequently, as shown in FIG. 8A, a transfer film 100 in which at least the low resistance layer 102 and the dielectric layer 103 are laminated on one main surface of the shadow mask base material 52 facing the electron gun assembly is formed. Install.

  That is, the transfer film 100 is configured by laminating a low resistance layer 102 and a dielectric layer 103 in this order on a base film 101 as shown in FIG. As described above, the low resistance layer 102 is made of a conductive material or the like mainly composed of lead borosilicate glass containing silver, and further contains a photosensitive resin. In addition, as described above, the dielectric layer 103 is made of an insulating material mainly composed of bismuth-based borosilicate glass, and further contains a photosensitive resin. The photosensitive resin contained in the low-resistance layer 102 and the dielectric layer 103 causes a crosslinking reaction upon irradiation with light having a predetermined wavelength and becomes insoluble in a predetermined developer. The low resistance layer 102 and the dielectric layer 103 are light transmissive, that is, have a predetermined transmittance with respect to light having a predetermined wavelength for exposure. In the transfer film 100, a release agent may be disposed between the base film 101 and the low resistance layer 102, an adhesive may be disposed on the surface of the dielectric layer 103, and A protective film may be disposed on the surface of the dielectric layer 103.

  The transfer film 100 having such a structure is arranged with the dielectric layer 103 facing the shadow mask base material 52 and then pressed, or a combination of pressurization and heating is used for the shadow mask base material 52. Glued on the surface. Thereby, the dielectric layer 103 of the transfer film 100, the low resistance layer 102, and the base film 101 are laminated | stacked on the shadow mask base material 52 in this order.

  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 low resistance layer 102 and the dielectric layer 103 of the transfer film 100 may be exposed corresponding to a predetermined pattern. That is, when the base film 101 has light transmittance, that is, when it has a predetermined transmittance with respect to light having a predetermined wavelength for exposure, the transfer film in a state in which the base film 101 is provided. By exposing 100, the low resistance layer 102 and the dielectric layer 103 are exposed. Further, when the base film 101 has a light shielding property, the base film 101 is removed before the exposure process, and the low resistance layer 102 and the dielectric layer 103 are directly exposed. Thus, the base film 101 of the transfer film 100 is removed before or after the exposure process.

  Note that the photomask PM applied in this exposure step has a striped opening pattern corresponding to both sides of each aperture row 19 formed in the shadow mask substrate 52. That is, in a state where the photomask PM is aligned on the transfer film 100, the aperture rows including the apertures 34 of the shadow mask substrate 52 are shielded from light, and the transfer film 100 between the aperture rows is exposed in a stripe shape. Will be.

  Subsequently, as shown in FIG. 8C, the exposed transfer film 100 is developed under a predetermined condition using a predetermined developer. In this development process, the low resistance layer 102 and the dielectric layer 103 of the transfer film 100 are selectively removed simultaneously. That is, since the low resistance layer 102 and the dielectric layer 103 of the transfer film 100 employed in this embodiment contain a so-called negative type photosensitive resin, the unexposed low resistance layer 102 and the dielectric layer 103 are Removed. That is, the low resistance layer 102 and the dielectric layer 103 located on the aperture rows including the apertures 34 of the shadow mask substrate 52 are removed, and the low resistance layer 102 and the dielectric layer 103 located between the aperture rows are removed. It remains in stripes.

  Subsequently, the low resistance layer 102 and the dielectric layer 103 remaining on the shadow mask substrate 52 are baked. As a result, the protruding portion 50 including the dielectric layer 50A and the low resistance layer 50B is formed on the shadow mask base material 52.

  Through the above steps, the shadow mask 12 having a predetermined shape having the stripe-shaped protrusions 50 on the surface on the electron gun assembly side is obtained.

  According to such a manufacturing method, after the transfer film 100 in which the low resistance layer 102 and the dielectric layer 103 are laminated is provided on one main surface of the shadow mask base material 52 and exposed through a predetermined photomask PM. By developing, the dielectric layer 50A and the low resistance layer 50B having a predetermined pattern can be collectively formed on the shadow mask substrate 52. Accordingly, the number of manufacturing steps can be reduced, and the manufacturing time can be shortened because the process is simpler than the conventional film forming step. As a result, the manufacturing cost can be reduced and the manufacturing yield can be improved.

  The dielectric layer 50A and the low resistance layer 50B are formed by a single photolithography process through the same photomask PM. Therefore, the dielectric layer 50A and the low resistance layer 50B have substantially the same width. Therefore, the peripheral portion of the dielectric layer 50A is not exposed from the low-resistance layer 50B, and unwanted charging of the dielectric layer 50A can be suppressed. Thereby, the focusing performance of the electron beam can be maintained in a stable state. Further, by adopting such a photolithography process, it is possible to form a high-precision dielectric layer and a low-resistance layer even for a high-definition shadow mask with a fine aperture pitch.

  Next, another method for manufacturing a shadow mask will be described. Also in this embodiment, the dielectric layer 50A and the low resistance layer 50B are simultaneously formed on the shadow mask 12 in the same process using the transfer film in which the dielectric layer and the low resistance layer are laminated. The form and the structure of the transfer film to be applied are slightly different.

  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 further a low resistance layer 102 and a dielectric layer 103 on the photoresist layer 104. The layers are stacked in this order. Similar to the above-described embodiment, the low resistance layer 102 is formed of a conductive material mainly composed of lead borosilicate glass containing silver, and the dielectric layer 103 is formed of bismuth borosilicate. It is made of an insulating material mainly composed of glass. In the case of the transfer film 100 having such a structure, the low resistance layer 102 and the dielectric layer 103 do not need to contain a photosensitive resin. The photoresist layer 104 undergoes a cross-linking reaction by irradiation with light having a predetermined wavelength and becomes insoluble in a predetermined developer. In the 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, A protective film may be disposed on the surface of the dielectric layer 103.

  In the shadow mask manufacturing method according to this embodiment, first, a rectangular plate-shaped shadow mask base material 52 such as an amber material is prepared, and a large number of holes 34 are regularly drilled in a region to be the perforated portion 20a. Then, press molding is performed under predetermined conditions.

  Subsequently, as shown in FIG. 11A, at least the low resistance layer 102, the dielectric layer 103, and the photoresist layer 104 are laminated on one main surface of the shadow mask base material 52 facing the electron gun assembly. The transferred transfer film 100 is installed. Thus, the dielectric layer 103, the low resistance layer 102, the photoresist layer 104, and the base film 101 of the transfer film 100 are laminated on the shadow mask base material 52 in this order.

  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 corresponding to 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 with the base film 101 provided thereon. Further, when the base film 101 has a light shielding property, the base film 101 is removed before the exposure process, and the photoresist layer 104 is directly exposed. Note that the photomask PM applied in this exposure step has a striped opening pattern corresponding to both sides of each aperture row 19 formed in the shadow mask substrate 52.

  Subsequently, as shown in FIG. 11C, the exposed transfer film 100 is developed under a predetermined condition using a predetermined developer. In this development process, 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. In other words, the photoresist layer 104 located on the aperture rows including the apertures 34 of the shadow mask substrate 52 is removed, and the photoresist layer 104 positioned between the aperture rows remains in a stripe shape.

  Subsequently, as shown in FIG. 11D, the portion where the photoresist layer 104 is removed and the low resistance layer 102 is exposed is removed by etching under a predetermined condition. In this etching process, the exposed low resistance layer 102 and dielectric layer 103 are simultaneously removed. As a result, the low resistance layer 102 and the dielectric layer 103 located on the aperture row including the aperture 34 of the shadow mask substrate 52 are removed. Thereafter, the remaining photoresist layer 104 is removed, so that the low resistance layer 102 and the dielectric layer 103 located between the aperture rows remain in a stripe shape.

  In this embodiment, the developing process and the etching process are performed in separate processes. However, by selecting an appropriate developing solution and setting appropriate developing conditions, the developing process and low resistance of the photoresist layer 104 are performed. It is also possible to simultaneously perform the etching process on the layer 102 and the dielectric layer 103 at the same time.

  Subsequently, the low resistance layer 102 and the dielectric layer 103 remaining on the shadow mask substrate 52 are baked. As a result, the protruding portion 50 including the dielectric layer 50A and the low resistance layer 50B is formed on the shadow mask base material 52.

  Through the above steps, the shadow mask 12 having a predetermined shape having the stripe-shaped protrusions 50 on the surface on the electron gun assembly side is obtained. In such an embodiment, the same effect as described above can be obtained.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention. For example, the opening formed in the shadow mask is not limited to a rectangular shape, and may be a circular shape, and the phosphor layer on the phosphor screen side is not limited to a stripe shape but may be a dot shape. Furthermore, the dielectric layer 50A only needs to be provided on both sides of each aperture 34 so as to form a quadrupole lens, and is not limited to a stripe shape, but is patterned into a desired shape such as an island shape or a dot shape. It is good also as a composition. Similarly, the dimensions and shapes of the respective parts shown in the above-described embodiments are merely examples, and various modifications can be made as necessary.

FIG. 1 is a horizontal sectional view schematically showing the 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 the phosphor screen in the color cathode ray tube shown in FIG. 3A is a perspective view schematically showing the structure of the shadow mask in the color cathode ray tube shown in FIG. 1, and FIG. 3B is a plan view showing a part of the shadow mask in an enlarged manner. FIG. FIG. 4 is a diagram schematically showing the relationship between the shadow mask, the phosphor screen, and the electron beam. FIG. 5 is a perspective view schematically showing the structure of the surface of the shadow mask on which the protrusion is formed, on the electron gun assembly side. FIG. 6 is a diagram schematically showing a focus state of the electron beam passing through the central portion of the perforated portion of the shadow mask. FIG. 7 is a plan view showing a shadow mask base material applied to the shadow mask manufacturing method. FIGS. 8A to 8C are views for explaining a shadow mask manufacturing method according to one embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing the structure of a transfer film applied to the shadow mask manufacturing method shown in FIG. FIG. 10 is a cross-sectional view schematically showing the structure of a transfer film applied to another embodiment. FIGS. 11A to 11D are views for explaining a method of manufacturing a shadow mask according to another embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 6 ... Phosphor screen, 9 ... Electron gun structure, 10 ... Vacuum envelope, 12 ... Shadow mask, 19 ... Opening row, 20 ... Mask main surface, 20a ... Perforated part, 34 ... Opening, 42R, 42G 42B ... phosphor layer, 50 ... protruding portion, 50A ... dielectric layer, 50B ... low resistance layer, 52 ... mask substrate, 100 ... transfer film, 102 ... low resistance layer, 103 ... dielectric layer

Claims (13)

An envelope having a panel having a phosphor screen disposed on the inner surface, an electron gun disposed in the envelope and emitting an electron beam toward the phosphor screen, and facing the phosphor screen And a shadow mask manufacturing method applied to a color cathode ray tube including a shadow mask having a plurality of apertures for selecting an electron beam emitted from the electron gun.
Providing a transfer film in which at least a dielectric layer and a low resistance layer are laminated on one main surface facing the electron gun assembly of a shadow mask base material having a plurality of regularly perforated holes;
Exposing the transfer film through a photomask having a predetermined pattern;
Developing the transfer film;
Firing the dielectric layer and the low resistance layer remaining on the shadow mask substrate;
A method of manufacturing a shadow mask, comprising: An envelope having a panel having a phosphor screen disposed on the inner surface, an electron gun disposed in the envelope and emitting an electron beam toward the phosphor screen, and facing the phosphor screen And a shadow mask manufacturing method applied to a color cathode ray tube including a shadow mask having a plurality of apertures for selecting an electron beam emitted from the electron gun.
At least a dielectric layer and a low resistance layer are laminated on one main surface of the shadow mask base material having a plurality of regularly drilled holes facing the electron gun assembly, and the dielectric layer and the low resistance layer A step of providing a transfer film containing a photosensitive resin,
Exposing the low-resistance layer and the dielectric layer of the transfer film through a photomask having a predetermined pattern;
Developing the transfer film to remove the unexposed dielectric layer and the low resistance layer;
Firing the dielectric layer and the low resistance layer remaining on the shadow mask substrate;
A method of manufacturing a shadow mask, comprising: An envelope having a panel having a phosphor screen disposed on the inner surface, an electron gun disposed in the envelope and emitting an electron beam toward the phosphor screen, and facing the phosphor screen And a shadow mask manufacturing method applied to a color cathode ray tube including a shadow mask having a plurality of apertures for selecting an electron beam emitted from the electron gun.
The low resistance layer is formed by laminating at least a base film in order of a low resistance layer and a dielectric layer on one main surface of the shadow mask base material having a plurality of regularly drilled holes facing the electron gun assembly. And a step of providing a transfer film having optical transparency with both the dielectric layers;
Exposing the low-resistance layer and the dielectric layer of the transfer film through a photomask having a predetermined pattern;
Removing the base film from the transfer film;
Developing the transfer film;
Firing the dielectric layer and the low resistance layer remaining on the shadow mask substrate;
A method of manufacturing a shadow mask, comprising:   The shadow mask manufacturing method according to any one of claims 1 to 3, wherein the low resistance layer and the dielectric layer are formed in a stripe shape around an opening in the shadow mask base material. Method.   4. The low resistance layer and the dielectric layer are arranged in parallel to a row of holes formed of a plurality of holes arranged in a minor axis direction of the shadow mask base material. The manufacturing method of the shadow mask of any one of Claims 1.   4. The method of manufacturing a shadow mask according to claim 1, wherein the low resistance layer has a width equal to a width of the dielectric layer. 5.   4. The method of manufacturing a shadow mask according to claim 1, wherein the dielectric layer is formed of an insulating material mainly composed of bismuth-based borosilicate glass.   4. The method of manufacturing a shadow mask according to claim 1, wherein the low-resistance layer is formed of a conductive material whose main component is lead-borosilicate glass containing silver. 5.   The shadow mask manufacturing method according to any one of claims 1 to 3, wherein the transfer film is pressed onto the shadow mask base material, or is bonded by using pressure and heating together. Method.   The method of manufacturing a shadow mask according to claim 1, wherein the low resistance layer and the dielectric layer contain a photosensitive resin.   The method of manufacturing a shadow mask according to claim 1, wherein the transfer film is configured by laminating the low resistance layer and the dielectric layer in this order on a base film.   4. The method of manufacturing a shadow mask according to claim 1, wherein the dielectric layer and the low-resistance layer are laminated in this order on the shadow mask base material. 5.   4. The shadow mask substrate according to claim 1, wherein the dielectric layer and the low-resistance layer are formed after a plurality of apertures are regularly perforated and press-molded. 2. A method for producing a shadow mask according to item 1.

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