WO2000046833A1

WO2000046833A1 - Shadowmask for cathode-ray tube

Info

Publication number: WO2000046833A1
Application number: PCT/JP2000/000487
Authority: WO
Inventors: Akira Makita; Takeshi Ikegami; Yoshinori Hirobe
Original assignee: Dai Nippon Printing Co., Ltd.
Priority date: 1999-02-01
Filing date: 2000-01-28
Publication date: 2000-08-10
Also published as: KR20010042220A; JP2000294161A; CN1146949C; CN1296636A; DE10080397T1

Abstract

A shadowmask (1) comprising an extra slit (4) which is provided outside a slit (2) made in at least one edge of the shadowmask (1). The extra slit (4) has a cross section defined by a through width (W) defined by the edge (23) on the light source side of the mask (22) on the central side of the shadowmask and the edge (26) on the fluorescent screen side of the mask (29) on the periphery side of the shadowmask, an opening width (T) defined by the mask end face edges (24, 28) on both sides in the direction toward the fluorescent screen, and an opening width (S) defined by the mask end face edges (25, 27) on both side in the direction toward the light source. The position (P) of the center of the opening width (T) is shifted from the position (Q) of the center of the opening width (S) toward the center of the shadowmask. The opening width (T) and the opening width (S) are greater than the through width (Y) of the slit (2) defined by the mask end face edges on both sides in the direction toward the light source.

Description

Description-CRT shadow mask Technical field

The present invention relates to a shadow mask for a cathode-ray tube, and more particularly, it includes a plurality of slits and a mask formed by an etching process, and the mask uses the mask to irradiate a light emitted from a light source of the cathode-ray tube to a phosphor screen. An aperture-grill (hereinafter referred to as “AG”) shaped shadow mask for a CRT. Background art

FIG. 5 is a schematic perspective view showing an example of the structure of an AG type color CRT. The AG type color cathode ray tube 51 converges three electron beams arranged in-line in the single electron gun 52 while crossing them at the center of one main lens, and then, by electrostatic deflection, to the shadow mask 53. The cathode ray tube is a cathode ray tube that intensively passes formed slits and lands on the corresponding phosphor on the vertical stripe-shaped phosphor screen 54 to emit light.

The shadow mask 53 is used for landing the electron beam at a predetermined position with a predetermined width to select colors of the AG type color cathode ray tube 51. The shadow mask 53 is formed into a desired shape by etching a thin metal plate, and is composed of a slit in the vertical direction and an ID mask. Such a shadow mask 53 is attached to the steel frame 61 with an appropriate tension as shown in FIGS. 6A and 6B, and is fixed with high positional accuracy so that the interdigital mask does not vibrate. The method for attaching the shadow mask 53 to the steel frame 61 is as shown in Fig. 6 (A). The upper and lower sides of the shadow mask 53 are pressed while applying pressure to the four or more places of the steel frame 61 from above and below at a predetermined pressure F, while keeping the steel frame 61 deformed within the elastic limit. There is a method of joining and attaching to the steel frame 61 by welding such as resistance heating welding or laser one-beam welding. The shadow mask 53 welded in this manner is fixed at an appropriate tension by removing the pressure F applied to the steel frame 61.

The welding at this time is usually performed by aligning the steel frame 61 and the shadow mask 53, from one end to the other end, or from near the center to both ends. At this time, wrinkles due to welding distortion and the like are generated on the upper side and the lower side of the shadow mask 53 welded to the steel frame 61 as welding progresses, and gradually accumulate. As a result, near the end on the side where welding is completed, the accumulated wrinkles may cause a phenomenon such that the slit shape is deformed. Such a phenomenon causes a problem that a predetermined slit width cannot be maintained uniformly over the entire shadow mask. For example, when the shadow mask 53 is welded from one end of the steel frame 61 to the other end, the slit at the end in the direction to be welded is accumulated due to accumulation of wrinkles. When the shadow mask 53 is welded from the center of the steel frame 61 toward both ends when the slit width is reduced due to the deformation of the slit, the slits at both ends of the shadow mask 53 If the slit width is reduced due to deformation, some problems may occur.

As shadow masks for solving such a problem, Japanese Patent Application Laid-Open Nos. 5-159716 and 5-314920 are disclosed. FIGS. 4 (A) and 4 (B) are schematic diagrams showing the relationship between an extra slit 44 formed on those shadow masks and a fluorescent screen 54. FIG. The extrusion slit shown in FIG. 4 (A) has the same cross-sectional shape as the slit of the effective screen section, and has a small opening width on the light source side and a large opening width on the phosphor screen side. The extra slit in FIG. 4 (B) is obtained by etching from both the light source side and the phosphor screen side, and is formed by shifting the pattern on the phosphor screen side and the light source side. These extra slits 44 have a slit in the effective screen section for the purpose of absorbing variations in the extreme slit width and shielding the electron beam so that exposure by the extra slits does not occur. It is formed with a through width Z of a narrow width of 40 to 70% of the gate width.

However, since such an extra slit 44 needs to be formed with a smaller penetration width than the slit of the effective screen portion, higher etching accuracy is required than in the case of forming the slit of the effective screen portion. You. Therefore, there is a manufacturing problem that the formation is difficult. This tendency is particularly pronounced in the case of shadow masks used for cathode ray tubes that require high definition. Furthermore, since the penetration width Z is small, if the accumulation of wrinkles generated by welding distortion, etc. is large, the wrinkles cannot be sufficiently absorbed, and the width of the slit at the end is set to the predetermined width. May not be maintained. Disclosure of the invention

The present invention solves the above problems by absorbing the deformation of the slit caused by wrinkles caused by welding distortion and the like. Further, the present invention makes it easier to form the slit and to reduce the fluorescent surface of the cathode ray tube. Provided is a shadow mask for a cathode ray tube having an extra slit capable of obtaining an irradiation width smaller than an exposure width.

Hereinafter, the present invention will be described with reference to the drawings showing the embodiments. However, the present invention is not limited to the illustrated embodiment.

The CRT shadow mask of the present invention includes a plurality of slits 2 formed by etching and a mask 3. In the shadow mask 1 for a cathode ray tube in which the irradiation width X of light emitted from the light source of the cathode ray tube to the fluorescent screen 54 is determined, at least one of slits 2 provided at both ends of the shadow mask 1 is slit. Further, an extra slit 4 is provided on the outside of the mask, and the extra slit 4 has a light source side end portion 23 of the mask 22 on the center side of the shadow mask and a fluorescent light of the mask 29 on the outer peripheral side of the shadow mask. Penetration width W defined by surface side edge 26, mask width edge T2 defined between mask edge edges 24, 28 on both sides in the fluorescent screen side, and mask edge edge 25 on both sides in the light source direction 27, and an opening width S defined between 27, and furthermore, the center of the opening width T defined between the mask end faces 24, 28 on both sides in the direction of the fluorescent screen side. Position P is on both sides in the light source side direction. The opening width T and the opening width S are shifted to the center side of the shadow mask from the center position Q of the opening width S defined between the mask end face edges 25 and 27. It is characterized in that it has a penetration width Y or more defined between the mask edge faces on both sides in the light source side direction.

According to the present invention, the opening width T and the opening width S forming the cross-sectional shape of the extra slit 4 are formed to be equal to or larger than the penetration width Y defined between the mask end face edges on both sides of the slit 2 in the light source side. Therefore, etching can be easily performed with a larger mask pattern than that for forming the slit 2. The extra slit 4 is provided outside the slit 2 at one end, and the light source side end 23 of the mask 2 at the center of the shadow mask 1 and the mask at the outer peripheral side of the shadow mask 1 are provided. 29 has a penetration width W defined by the end 26 on the phosphor screen side, and an opening width T defined between the mask end faces 24 and 28 on both sides in the direction of the phosphor screen. Since the center position P is shifted toward the center of the shadow mask with respect to the center position Q of the opening width S defined between the mask edge surfaces 25 and 27 on both sides in the light source side, the light source described above is used. ~ side The end 23 and the end 26 on the phosphor screen side are formed at different positions in the coordinate position in the direction orthogonal to the shadow mask plane. As a result, even when the mask 22 on the center side of the shadow mask approaches the mask 29 on the outer peripheral side of the shadow mask when the wrinkles generated during welding are absorbed, the end 23 on the light source side and the phosphor screen are not affected. The end 26 on the side does not hit the opposing part if the length is less than the penetration width W. The extra slit 4 obtained in this way can absorb the wrinkles generated when the shadow mask 1 is welded to the steel frame 61, so that at least one of the slits 2 at one end is prevented from being deformed by the wrinkles. Thus, the effective width of all the slits 2 formed in the shadow mask 1 can be secured.

Further, in the shadow mask for a cathode ray tube according to the present invention, the irradiation width X of the light passing through the extra slit 4 is smaller than the exposure width of the fluorescent screen 54, and A part of the light 21 incident obliquely is shielded by the mask end face edge 25 toward the light source at the center of the shadow mask and the mask end face edge 28 toward the phosphor screen at the outer periphery of the shadow mask. It is unique that it is determined.

According to the present invention, since the irradiation width X of the light passing through the extra slit 4 is smaller than the exposure width of the phosphor screen 54, even if wrinkles do not occur when the shadow mask 1 is welded, the fluorescence The surface 54 is not exposed. As described above, in the extra slit 4, the center position P of the opening width T is shifted toward the center of the shadow mask with respect to the center position Q of the opening width S. Part of the obliquely incident light 21 is shielded by the mask end face edge 25 toward the light source at the center of the shadow mask and the mask end face edge 28 toward the phosphor screen at the outer periphery of the shadow mask. As determined, the extra slit 4 acts to make the irradiation width X smaller when absorbing wrinkles during welding of the shadow mask 1, No exposure of the phosphor screen occurs. ―

Furthermore, the present invention provides the shadow mask for a cathode ray tube described above, wherein the light source side end 23 of the mask on the center side of the shadow mask and the phosphor screen side end 26 of the mask on the outer side of the shadow mask are: It is characterized in that it is formed at a distance of 5 / m or more as a coordinate position length ΔΗ in a direction orthogonal to the shadow mask surface.

According to the present invention, the light source side end 23 of the mask on the shadow mask center side and the phosphor screen side end 26 of the mask on the shadow mask outer peripheral side are coordinate position lengths in a direction orthogonal to the shadow mask surface. Since it is formed at a distance of 5 m or more as Δ Δ, the mask 22 on the center side of the shadow mask approaches the mask 29 on the outer side of the shadow mask when the wrinkles generated during welding are absorbed. However, the light source side end portion 23 and the phosphor screen side end portion 26 do not abut each other when the length is not more than the penetration width W. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view showing an example of a shadow mask for an aperture-Daryl-type color CRT of the present invention. FIG. 2 is an enlarged cross-sectional view showing an example of a cross-sectional shape of a slit and an extra slit formed on the shadow mask of the present invention. FIG. 3 is an enlarged cross-sectional view showing another example of the cross-sectional shape of the extra slit formed on the shadow mask of the present invention. FIG. 4 is a schematic diagram showing a relationship between an extra slit formed on a conventional shadow mask and a phosphor screen. FIG. 5 is a schematic perspective view showing the structure of an aperture-grill type empty tube. FIG. 6 is a front view (A) and a longitudinal cross-sectional view (B) showing a state where a steel frame is welded by applying tension. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described with reference to the drawings. ―

FIG. 1 is a plan view showing an example of a shadow mask for an A-G color CRT according to the present invention. The shadow mask 1 has a plurality of slits 2 and a mask 3, and is formed by etching a substantially rectangular thin metal plate. The mask 3 acts to block extra light among the light emitted from the light source of the cathode ray tube at a predetermined angle Θ. Of the light emitted from the light source of the cathode ray tube, the light that should reach the phosphor screen passes through the slit 2 that has been etched to a predetermined width, and the irradiation width is determined by the shape and dimensions of the mask 3 . Extra slits 4 are provided further outside the left and right slits of the shadow mask 1. The upper side 6 and the lower side 7 of the shadow mask 1 are welded to a separately prepared steel frame 61 (see Fig. 6) so that the shadow mask 1 can be held down with an appropriate tension. Part. As the metal sheet, a material having a small coefficient of thermal expansion, such as a nickel-iron alloy, or an iron-based material having improved creep characteristics is usually used.

FIG. 2 is an enlarged cross-sectional view showing an example of a cross-sectional shape of a slit and an extruded slit formed on the shadow mask of the present invention. FIG. 3 is an enlarged sectional view showing another example of the sectional shape of the extra slit formed on the shadow mask of the present invention. In the extra slit shown in FIG. 2, the light source side end 23 of the mask 22 on the center side of the shadow mask and the mask end surface edge 25 are common, and the fluorescent surface of the mask 29 on the outer side of the shadow mask is also used. The side end portion 26 and the mask end surface edge 28 have a common cross-sectional shape. On the other hand, the extra slits shown in FIG. 3 have different cross-sectional shapes.

As shown in Fig. 5, when the shadow mask 1 is mounted on the cathode ray tube 51, the slit 2 exposes the fluorescent screen 54 inside the panel 55 to vertical stripes. It acts to pass ultraviolet light for irradiating, or to color-select the irradiation light when the three electron beams emitted from the electron gun 52 are concentrated and passed. Then, the irradiation light that has passed through the slit 2 lands on the phosphor at the position corresponding to the vertical stripe-shaped phosphor screen 54 disposed inside the panel 55, and the phosphor emits light. . As shown in FIG. 2, such a slit 2 usually has a mortar shape with a small opening width on the light source side and a large opening width on the phosphor surface 54 side. It is formed with the number, pitch, penetration width Y and cross-sectional shape. In particular, the shadow mask 1 used for a high-definition color cathode ray tube has a small slit 2 and a small through-hole width Y, and requires more precise etching.

The extra slit 4 acts to absorb wrinkles generated by welding distortion and the like when the shadow mask 1 is welded, and to prevent deformation of the slit 2 shape at both ends. The extra slits 4 are formed at positions further outside the slits 2 at the left and right ends, and are formed by the same etching process as the formation of the slits 2.

By providing the extra slits 4 at the left and right ends, the shadow mask 1 can be welded from its center to both ends. Even when welding is performed from one end of the shadow mask to the other end, if the welding direction is not particularly determined, it is convenient to provide them at both ends in advance. When the welding direction is determined, the extra slit 4 can be provided only on the side where welding is completed. In order to sufficiently absorb the wrinkles generated by welding, it is preferable that the length of the extra slit 4 in the longitudinal direction is approximately the same as the length of the slit 2 in the longitudinal direction.

The cross-sectional shape of the extraslit 4 is as shown in Figs. 2 and 3. In the cross-sectional shape in the direction perpendicular to the shadow mask surface, the penetration defined by the light source side end 23 of the mask 22 on the center side of the shadow mask and the phosphor screen side end 26 of the mask 29 on the outer side of the shadow mask The width W, the opening width T defined between the mask end edges 24 and 28 on both sides in the fluorescent screen side direction, and the opening width S defined between the mask end edges 25 and 27 on both sides in the light source direction. It is composed of In addition, the center position P of the opening width T defined between the mask end edges 24 and 28 on both sides in the phosphor screen direction, and the opening defined between the mask end edges 25 and 27 on both sides in the light source direction. The opening width T and the opening width S are shifted from the center position Q of the width S to the center side of the shadow mask, so that the opening width T and the opening width S are defined between the mask edge edges on both sides of the slit 2 in the light source side. It has a cross-sectional shape with a width of Y or more. At this time, the penetration width W of the extra slit 4 may be larger or smaller than the penetration width Y of the slit 2 and is not particularly limited.

Accordingly, since the opening width T and the opening width S are formed to be equal to or larger than the through width Y of the slit 2, a mask mask for etching that is larger than the formation of the slit 2 can be used. . Therefore, an advanced slit is not required, and the extra slit 4 can be easily formed by a normal etching process.

As shown in FIG. 2, the light source side end 23 and the phosphor screen side end 26 constituting the extra slit 4 are formed in a shape like a knife edge formed on the surface of each mask. It may be common to the end faces 25 and 28, respectively, or may be a shape formed at a position slightly intruding from each mask surface as shown in FIG. The cross-sectional shape of the extra slit 4 can be appropriately set according to the etching conditions at the time of etching.

In the present invention, such a light source side end 23 and a phosphor screen side end 26 are formed. It is formed at a different position in the coordinate position in the direction orthogonal to the shadow mask surface. As a result, even when the mask 22 on the center of the shadow mask approaches the mask 29 on the outer periphery of the shadow mask when the wrinkles generated during welding are absorbed, the end 23 on the light source side and the fluorescent screen side The end 26 does not abut on an opposing portion if the length is not more than the penetration width W. The extra slit 4 obtained in this way can absorb wrinkles generated when the shadow mask 1 is welded to the steel frame 61, thereby preventing deformation due to wrinkles occurring at least at the slit 2 at one end. Thus, the effective width of all the slits 2 formed in the shadow mask 1 can be secured. The light 21 obliquely incident on the extra slit 4 is a mask end face edge 25 facing the light source side at the center of the shadow mask of the extra slit 4, and a mask facing the phosphor screen at the outer peripheral side of the shadow mask. A part thereof is shielded by the edge edges 28 and passes through the extra slit 4 with a predetermined irradiation width X to irradiate the fluorescent screen 54. The shift amount between the center position P of the opening width T and the center position Q of the opening width S is adjusted so that the irradiation width X is smaller than the width for exposing the phosphor screen 54. , 28 are formed in a predetermined positional relationship. As a result, the phosphor screen 54 is not exposed regardless of whether wrinkles occur when the shadow mask 1 is welded, and even when wrinkles occur, the irradiation width X is made smaller. As described above, the extra slit 4 acts, so that the phosphor screen is not exposed.

The positional relationship between the edges 25 and 28 is based on the difference in the incident angle of light 0 based on the difference in the size of the cathode ray tube on which the shadow mask 1 is mounted, and the thickness of the metal sheet used for the shadow mask 1. It is set appropriately according to differences, differences in etching processing conditions, differences in the exposing properties of the phosphor screen (phosphor screen material and ultraviolet intensity), etc., but the center position P of the opening width T and the center position Q of the opening width S Shi It is preferable that the shift is performed at a distance of 30 m or more on a coordinate axis orthogonal to the shadow mask plane.

The size of the opening width S on the light source side and the opening width T on the phosphor screen side can be appropriately set on condition that the above positional relationship is satisfied.

The light source side end 23 of the mask on the center side of the shadow mask and the phosphor screen side end 26 of the mask on the outer side of the shadow mask have a coordinate position length Δ の in a direction perpendicular to the shadow mask plane of 5 ^. Preferably, they are formed at a distance of at least m. As a result, when the wrinkles generated during welding are absorbed, even if the mask 22 on the shadow mask center side approaches the mask 29 on the shadow mask outer peripheral side, the light source side end 23 and the fluorescent screen side can be used. The end 26 does not abut on an opposing portion if the length is less than the penetration width W.

In addition, the fluorescent screen 54 of the ordinary cathode ray tube 51 may be exposed by irradiating it with a width exceeding 50 mm, so that the extra slit 4 has an irradiation width X of 50 or less. Is preferred. The degree of exposure of the phosphor screen 54 may vary depending on the photosensitive material that forms the phosphor screen and the exposure conditions such as the intensity of ultraviolet light used for exposure, so the exposure conditions should be considered in special cases. Then, the irradiation width X is appropriately determined. When the sensitivity and ultraviolet intensity of the phosphor are high, it is preferable to form an extra slit that makes the irradiation width X on the phosphor screen 54 smaller.

When the shadow mask 1 is welded to the steel frame 61 when welding is performed from one end of the shadow mask 1 to the other end, it is not always necessary to provide extra slits on both sides. It may be formed on one side.

The shadow mask 1 described above can be manufactured by a conventionally known method. Usually, it is performed in a series of steps using photo-etching technology. Manufactured on continuous in-line or off-line equipment. For example, first, a water-soluble colloidal photoresist is applied to both sides of a thin metal plate. After drying, the original plate for exposure is brought into close contact with both surfaces, exposed with ultraviolet-rich light such as high-pressure mercury, and developed with water. After the development, the exposed portions of the metal covered with the resist film are etched. As a result, as shown in FIGS. 2 and 3, the slit 2 etched in a mortar shape, the opening center P on the phosphor screen side and the opening center Q on the light source side are offset, and A shadow mask 1 having an extra slit 4 etched into a shape in which the opening center P on the side is shifted to the center side of the shadow mask 1 is manufactured. At this time, the pattern of the original exposure plate and the close contact position thereof are adjusted such that the shape of the extra slit 4 becomes the shape shown in FIG. 2 or FIG. The etching process is performed by spraying a ferric chloride solution from both sides of the metal sheet after heat treatment, etc., followed by continuous post-processing such as water washing and peeling. . Industrial applicability

As described above, according to the shadow mask for a cathode ray tube of the present invention, it is possible to easily perform an etching process with a mask pattern larger than the formation of the slit, so that the shadow mask can be easily manufactured. It can be preferably applied to a shadow mask used for a cathode ray tube which requires a higher definition. In addition, the phosphor screen is not exposed, regardless of whether wrinkles occur when the shadow mask is welded. Furthermore, even when the center of the shadow mask approaches the mask on the outer periphery of the shadow mask when the wrinkles generated during welding are absorbed, the light source side end and the phosphor screen side end have a penetration width W or less. With the length of, it will not hit the opposite part, so it can absorb the wrinkles that occur

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Claims

The scope of the claims -

1. A shadow mask for a CRT comprising a plurality of slits and a mask formed by an etching process, and the mask determines the irradiation width of light emitted from the light source of the CRT to the phosphor screen.

Among the slits provided at both ends of the shadow mask, at least one of the slits has an extra slit further outside the slit,

The extra slit has a penetration width W defined by the light source side end of the mask on the center side of the shadow mask and the fluorescent screen side end of the mask on the outer peripheral side of the shadow mask, and both sides in the fluorescent screen side direction. It has a cross-sectional shape consisting of an opening width T defined between mask edge edges and an opening width S defined between mask edge edges on both sides in the light source direction,

Further, the center position P of the opening width T defined between the mask end faces on both sides in the fluorescent screen side direction is different from the center position Q of the opening width S defined between the mask end faces on both sides in the light source direction. Is shifted toward the center of the shadow mask,

A shadow mask for a brown tube, wherein the opening width T and the opening width S are not less than a through width Y defined between mask edge edges on both sides of the slit in a light source side.

2. The shadow mask for a CRT according to claim 1, wherein an irradiation width X of light passing through the extra slit is smaller than an exposure width of the phosphor screen, and A part of the obliquely incident light is determined by being shielded by the mask end face edge in the light source direction at the shadow mask center side and the mask end face edge in the phosphor screen direction on the shadow mask outer peripheral side. Shadow mask for CRT.

3. Shadow cathode for a CRT according to claim 1 or 2. In the

The light source side end of the mask on the shadow mask center side and the phosphor screen side end of the shadow mask outer peripheral side mask have a coordinate position length Δ の in a direction orthogonal to the shadow mask surface, 5 ^. A shadow mask for a cathode ray tube, which is formed at a distance of at least m.