EP0039906A2 - Aperture mask for a color television tube, color television tube comprising such a mask and method for obtaining the mask - Google Patents
Aperture mask for a color television tube, color television tube comprising such a mask and method for obtaining the mask Download PDFInfo
- Publication number
- EP0039906A2 EP0039906A2 EP81103455A EP81103455A EP0039906A2 EP 0039906 A2 EP0039906 A2 EP 0039906A2 EP 81103455 A EP81103455 A EP 81103455A EP 81103455 A EP81103455 A EP 81103455A EP 0039906 A2 EP0039906 A2 EP 0039906A2
- Authority
- EP
- European Patent Office
- Prior art keywords
- opening
- recess
- aperture mask
- line
- openings
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/14—Manufacture of electrodes or electrode systems of non-emitting electrodes
- H01J9/142—Manufacture of electrodes or electrode systems of non-emitting electrodes of shadow-masks for colour television tubes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
- H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
- H01J29/06—Screens for shielding; Masks interposed in the electron stream
- H01J29/07—Shadow masks for colour television tubes
- H01J29/076—Shadow masks for colour television tubes characterised by the shape or distribution of beam-passing apertures
Definitions
- This invention relates generally to hole technology and to television picture tubes and, more specifically, to hole technology useful in television picture tubes having aperture masks with a plurality of line of sight openings therein.
- one part of the present invention comprises a method for making a line of sight opening which may be square, rectangular or the like and the second part comprises an article having a line of ⁇ sight opening which may be square, rectangular or the like.
- the article comprises a sheet of material having a line of sight opening wherein a portion of the edges of the line of sight opening-is partially defined by surface material located on one side of the article with the remainder of the edges of the line of sight opening defined by material located on the opposite side of the article.
- the process involves the selective removal of material from one surface of an article by milling or etching a recess in the article with at least a portion of the material removed by undercutting the surface of the article. After forming a recess, an opening is formed in the opposite side of the material by milling or etching an opening from the opposite side into the recess.
- reference numeral 10 generally defines a portion of a television aperture mask having a cone side surface 10A and a grade side surface 10B.
- Surface 10A is referred to as the cone side since the larger opening or recess 15 is located therein and surface 10B is referred to as the grade side.
- the grade side faces the electron guns while the cone side faces the television picture tue. This type of positioning provides the best pictures for conventional etched masks.
- Located in aperture mask 10 is a line of sight opening which has edges that are defined by the cone side surface 10A and the grade side surface 10B of aperture mask 10.
- a recess 15 which is defined in cone side surface 10A by pair of side edges 11 and 11A and a pair of end edges 14A and 16A which are all located in the plane of cone side surface 10A of aperture mask 10.
- Side edges 11 and 11A connect to end edges 14A and 16A to form a closed boundary in the plane of cone side surface 10A.
- edges 11, 11A and edges 14A and 16A define the junction of the side walls of recess 15 with the cone side surface 10A.
- the side walls of recess 15 include an undercut surface 14 and an undercut surface 16 which respectively connect to edge 14A and edge 16A.
- Surfaces 14 and 16 are undercut downward from cone side 10A and radially outward from edges 14A and 16A toward grade side 10B.
- the thickness of aperture mask 10 is denoted by T which usually ranges from .004" to .008".
- the length of un dercut is denoted by A.
- the undercut angle is denoted by a and the thickness of the remaining material that forms the bottom of recess 15 is denoted by T 1 with T 1 being substan tially less than the thickness T of aperture mask 10.
- Fig. 3 grade side
- the bottom view shows the outline of an elongated slot in grade side surface 10B which is defined by edge 12A, edge 12, edge 12B and edge 12C which are all located in the.plane of grade side surface 10B.
- Edges 12 and 12A are straight whereas edges 12B and 12C are curved.
- the portion of the opening to the outside of lines X-X defines the portion of the opening which contains curved edges 12B and 12C.
- the line of sight opening through aperture-mask 10 is formed by edges 12A and 12 which define the longitudinal opening and edges 14A and 16A which define the transverse portion of the line of sight openings. Note, in the grade side view (Fig. 3) edge 12 and edge 12A also define the longitudinal opening; and edges 14A and 16A define the transverse portion of the line of sight opening. Although the grade side view of aperture mask 10 is different from the cone side view of aperture mask 10, the line of sight opening through aperture mask 10 is the same.
- lines X-X which are located on both ends of the elongated slot, denote the separation point between the curvature of edges 12B and 12C and straight sections 12A and 12.
- lines X-X are located to the outside of edges 14A and 16A to thereby insure the line of sight opening in aperture mask 10 is comprised of a set of straight edges with substantially square corners.
- the curved ends are typical of cutting operations such as chemical etching.
- grade side surface 10B reveals an elongated opening therein which is substantially longer than the line of sight opening through the article
- the process of etching permits one to etch a recess 15 in aperture mask 10.
- the etching process is continued until it produces a recess 15 with undercut surfaces 14 and 16.
- the size and shape of undercut surface can be controlled by the amount of etchant and time of etching and is generally within the skill of those in the art.
- the elongated opening is etched from the opposite side. If desired, the elongated opening can be formed during the etching of the recess by simultaneously spraying etchant on opposite surfaces 10A and 10B. After etching, the elongated slot appears with radiused corners as shown in Fig. 3. In the process of forming the line of sight opening through the article, the etching continues until the etchant penetrates through the material of thickness T 1 . After penetration, the etchant is removed typically leaving an elongated opening such as defined by edges 12A, 12B, 12C and 12D. Lines X-X denote the radius portion of elongated opening which results from the etching action.
- FIG. 3 An inspection of Fig. 3 shows the radius portion 12B and 12C project onto surfaces 15 and 16.
- the radiused corners 12B and 12C of aperture mask 10 do not form a part of the line of sight opening in aperture mask 10. While.the article and method have been described with respect to rectangular openings, it is apparent the process can be used to make other unusually shaped line of sight openings which are difficult or impossible to make with conventional techniques.
- a conventional television aperture mask was etched having elongated slots with parallel sides and rounded ends.
- the dimensions of the slot were as follows:
- the measured light transmission through the slot was measured as 17.7 units.
- a second aperture mask was made in accordance with the present invention in which the outline of the line of sight opening had a substantially rectangular configuration in accordance with Figs. 1, 2 and 3.
- the dimension of the rectangular line of sight opening were as follows:
- the transmission through the opening was measured as 18.36 units or an increase of approximately 4 percent in light transmission.
- a compensation for the area revealed that the second mask actual ly had an approximately 6.5 percent greater light transmit sion capability.
- reference numeral 30 generally designates a cross sectional view of a television picture tube using the line of sight aperture mask of the present invention.
- the television picture tube comprises a glass enclosure 31 having a base 32 and prongs 33 thereon for attachment to the electronics of the television set.
- a focusing coil 35 that focuses the electron beam so the electron beams converge as they pass through openings 47 in aperture mask 48.
- a deflection coil 37 which sweeps the electron beam across aperture mask 48.
- the aperture mask 48 is located with a plurality of elongated openings 47 located therein.
- a phosphor strip 40 Located immediately behind elongated slots 47 is a phosphor strip 40. Although three phosphor strips are located behind each opening in the cross sectional view only one strip is visible in the cross sectional view. The phosphor strips comprise the primary colors red, blue and green which, when excited by the electrons, produce the proper color on face plate 39 of television picture tube 30.
- Figs. 5 and 6 respectively show a top view of a portion of the television aperture mask and a television picture tube and a side view of a television picture tube.
- the front glass envelope portion of the television picture tube is designated by reference numeral 39 with reference numerals 40, 41 and 42 designating the red, blue and green phosphor stripes which extend longitudinally parallel to the elongated openings which are located in aperture mask 48.
- Fig. 7 shows schematically the slot arrangement of a typical aperture mask having a series of elongated slots. Located between phosphor stripes 40, 41 and 42 is a suitable black light- absorbing medium that does not emit any color should it be struck by electrons.
- the aperture mask is denoted by reference numeral 48 and with cone side 45 facing the electron gun and the grade side 46 facing the phosphor _stripes which are located on face plate 34. Since the most metal is removed from side 45 to provide recess 45A, this side is denoted as the cone side and in the embodiment shown is located facing the electron gun. Typical prior art aperture masks the cone side was located facing the phosphor side.
- Fig. 5 reveals how the grade side edge surfaces 53 and 54 limit the electrons in the lateral direction.
- Fig. 6 shows a side view of aperture mask 48 with reference numeral 39 denoting the face plate and reference numeral 40 indicating a phosphor stripe.
- the aperture masks 48 has an opening 45A on the cone side 45 and an elongated opening on the opposite side.
- the tie bar or bridges as they refer to in the prior art are located with the narrow end of the bridge or tie bar facing the phosphor stripe 40 and the tie bar extending from the cone side.45 to grade side 46.
- Fig. 6 shows tie bar 50 to comprise a grade side surface 50B, a cone side surface 50A and an interior surface 51 on lower tie bar and an upper interior surface 52 on upper tie bar 50.
- the upper and lower boundaries of the line of sight opening in aperture mask 48 is defined by the junction of surface 52 with cone side surface 44 and junction of surface 51 with cone side surface 45.
- the plurality of tie bars located in the spaced relationship provide for accurate defining of an opening for the excitation of the phosphor stripes located along the television picture tube.
- the aperture masks have the cone side facing the electron gun, one should have the bottom of the recess region, which is located adjacent the sides of the line of sight openings, sufficiently flat or angled so that the electron beams that impinge on the bottom of the recess region do not deflect through the line of sight opening in the aperture mask.
- the bottom of the recess region is parallel to the mask cone side surface., one does not obtain scattering electron reflections through the line of sight openings.
- the portion of the recess side walls which do not define a portion of the line of sight opening should be set sufficiently far back from the line of sight opening in the aperture mask so that the path of the electron beam is not obstructed by the recess region side walls or the cone side surface of the aperture mask. In conventional mounting with the grade side toward the electron gun, these adjustments would not be necessary.
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Electrodes For Cathode-Ray Tubes (AREA)
- ing And Chemical Polishing (AREA)
Abstract
Description
- This invention relates generally to hole technology and to television picture tubes and, more specifically, to hole technology useful in television picture tubes having aperture masks with a plurality of line of sight openings therein.
- Briefly, one part of the present invention comprises a method for making a line of sight opening which may be square, rectangular or the like and the second part comprises an article having a line of \ sight opening which may be square, rectangular or the like. The article comprises a sheet of material having a line of sight opening wherein a portion of the edges of the line of sight opening-is partially defined by surface material located on one side of the article with the remainder of the edges of the line of sight opening defined by material located on the opposite side of the article.
- The process involves the selective removal of material from one surface of an article by milling or etching a recess in the article with at least a portion of the material removed by undercutting the surface of the article. After forming a recess, an opening is formed in the opposite side of the material by milling or etching an opening from the opposite side into the recess.
- Fig. 1 is a perspective view of a single line of sight opening in a television aperture mask;
- Fig. 2 is a top view or cone side view of the line of sight opening of Fig. 1;
- Fig. 3 is a bottom view or grade side view of the line of sight opening of Fig. 1;
- Fig. 4 is a cross sectional view of a television picture tube;
- Fig. 5 is a partial top sectional view of an aperture mask and television tube;
- Fig. 6 is a partial side sectional view of an aperture mask and television tube; and
- Fig. 7 is a front schematic view of an aperture mask having a plurality of openings therein.
- Referring to Figs. 1, 2 and 3,
reference numeral 10 generally defines a portion of a television aperture mask having a cone side surface 10A and a grade side surface 10B. Surface 10A is referred to as the cone side since the larger opening orrecess 15 is located therein and surface 10B is referred to as the grade side. In typical use of an aperture mask in a television picture tube the grade side faces the electron guns while the cone side faces the television picture tue. This type of positioning provides the best pictures for conventional etched masks. Located inaperture mask 10 is a line of sight opening which has edges that are defined by the cone side surface 10A and the grade side surface 10B ofaperture mask 10. Located in cone side surface 10A is arecess 15 which is defined in cone side surface 10A by pair of side edges 11 and 11A and a pair ofend edges aperture mask 10. Side edges 11 and 11A connect toend edges edges recess 15 with the cone side surface 10A. - The side walls of
recess 15 include anundercut surface 14 and anundercut surface 16 which respectively connect toedge 14A andedge 16A.Surfaces edges - The thickness of
aperture mask 10 is denoted by T which usually ranges from .004" to .008". The length of un dercut is denoted by A. The undercut angle is denoted by a and the thickness of the remaining material that forms the bottom ofrecess 15 is denoted by T1 with T1 being substan tially less than the thickness T ofaperture mask 10. - Referring to Fig. 3 (grade side), it will be noted that the bottom view shows the outline of an elongated slot in grade side surface 10B which is defined by
edge 12A,edge 12,edge 12B andedge 12C which are all located in the.plane of grade side surface 10B.Edges edges curved edges - The line of sight opening through aperture-
mask 10 is formed byedges edges edge 12 andedge 12A also define the longitudinal opening; andedges aperture mask 10 is different from the cone side view ofaperture mask 10, the line of sight opening throughaperture mask 10 is the same. - The two lines X-X, which are located on both ends of the elongated slot, denote the separation point between the curvature of
edges straight sections edges aperture mask 10 is comprised of a set of straight edges with substantially square corners. The curved ends are typical of cutting operations such as chemical etching. - Thus, although grade side surface 10B reveals an elongated opening therein which is substantially longer than the line of sight opening through the article, the
surfaces edges radiused edges aperture mask 10. - In forming elongated openings in aperture mask, the process of etching permits one to etch a
recess 15 inaperture mask 10. Typically, the etching process is continued until it produces arecess 15 withundercut surfaces - After forming
recess 15 in one side, the elongated opening is etched from the opposite side. If desired, the elongated opening can be formed during the etching of the recess by simultaneously spraying etchant on opposite surfaces 10A and 10B. After etching, the elongated slot appears with radiused corners as shown in Fig. 3. In the process of forming the line of sight opening through the article, the etching continues until the etchant penetrates through the material of thickness T1. After penetration, the etchant is removed typically leaving an elongated opening such as defined byedges - An inspection of Fig. 3 shows the
radius portion surfaces radiused corners aperture mask 10 do not form a part of the line of sight opening inaperture mask 10. While.the article and method have been described with respect to rectangular openings, it is apparent the process can be used to make other unusually shaped line of sight openings which are difficult or impossible to make with conventional techniques. -
- The measured light transmission through the slot was measured as 17.7 units.
-
- The transmission through the opening was measured as 18.36 units or an increase of approximately 4 percent in light transmission. For the second mask, however, since the dimensions of the two holes were not exactly equal, a compensation for the area revealed that the second mask actual ly had an approximately 6.5 percent greater light transmit sion capability.
- Referring to Fig. 4,
reference numeral 30 generally designates a cross sectional view of a television picture tube using the line of sight aperture mask of the present invention. The television picture tube comprises aglass enclosure 31 having a base 32 and prongs 33 thereon for attachment to the electronics of the television set. - Located on the exterior of the neck of television picture tube is a focusing
coil 35 that focuses the electron beam so the electron beams converge as they pass throughopenings 47 inaperture mask 48. Located adjacent focusingcoil 35 is adeflection coil 37 which sweeps the electron beam acrossaperture mask 48. Theaperture mask 48 is located with a plurality ofelongated openings 47 located therein. Located immediately behindelongated slots 47 is aphosphor strip 40. Although three phosphor strips are located behind each opening in the cross sectional view only one strip is visible in the cross sectional view. The phosphor strips comprise the primary colors red, blue and green which, when excited by the electrons, produce the proper color onface plate 39 oftelevision picture tube 30. - To understand the operation of the present invention in a television picture tube, reference should be made to Figs. 5 and 6 which respectively show a top view of a portion of the television aperture mask and a television picture tube and a side view of a television picture tube. The front glass envelope portion of the television picture tube is designated by
reference numeral 39 withreference numerals aperture mask 48. Fig. 7 shows schematically the slot arrangement of a typical aperture mask having a series of elongated slots. Located betweenphosphor stripes - Referring to Fig. 5, the aperture mask is denoted by
reference numeral 48 and withcone side 45 facing the electron gun and thegrade side 46 facing the phosphor _stripes which are located onface plate 34. Since the most metal is removed fromside 45 to providerecess 45A, this side is denoted as the cone side and in the embodiment shown is located facing the electron gun. Typical prior art aperture masks the cone side was located facing the phosphor side. Fig. 5 reveals how the grade side edge surfaces 53 and 54 limit the electrons in the lateral direction. - Fig. 6 shows a side view of
aperture mask 48 withreference numeral 39 denoting the face plate andreference numeral 40 indicating a phosphor stripe. The aperture masks 48 has anopening 45A on thecone side 45 and an elongated opening on the opposite side. The tie bar or bridges as they refer to in the prior art are located with the narrow end of the bridge or tie bar facing thephosphor stripe 40 and the tie bar extending from the cone side.45 tograde side 46. Fig. 6 showstie bar 50 to comprise agrade side surface 50B, acone side surface 50A and aninterior surface 51 on lower tie bar and an upperinterior surface 52 onupper tie bar 50. The upper and lower boundaries of the line of sight opening inaperture mask 48 is defined by the junction ofsurface 52 with cone side surface 44 and junction ofsurface 51 withcone side surface 45. - In practice the plurality of tie bars located in the spaced relationship provide for accurate defining of an opening for the excitation of the phosphor stripes located along the television picture tube.
- Note, if the aperture masks have the cone side facing the electron gun, one should have the bottom of the recess region, which is located adjacent the sides of the line of sight openings, sufficiently flat or angled so that the electron beams that impinge on the bottom of the recess region do not deflect through the line of sight opening in the aperture mask. Typically, if the bottom of the recess region is parallel to the mask cone side surface., one does not obtain scattering electron reflections through the line of sight openings.
- In addition, with the aperture mask cone side facing the electron guns the portion of the recess side walls which do not define a portion of the line of sight opening should be set sufficiently far back from the line of sight opening in the aperture mask so that the path of the electron beam is not obstructed by the recess region side walls or the cone side surface of the aperture mask. In conventional mounting with the grade side toward the electron gun, these adjustments would not be necessary.
Claims (13)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT81103455T ATE22367T1 (en) | 1980-05-12 | 1981-05-07 | SHADOW MASK FOR A COLOR TELEVISION TUBE, COLOR TELEVISION TUBE WITH SUCH MASK AND METHOD OF MAKING THE MASK. |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14868280A | 1980-05-12 | 1980-05-12 | |
US148683 | 1980-05-12 | ||
US06/148,683 US4353948A (en) | 1980-05-12 | 1980-05-12 | Hole technology |
US148682 | 1980-05-12 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP0039906A2 true EP0039906A2 (en) | 1981-11-18 |
EP0039906A3 EP0039906A3 (en) | 1982-06-16 |
EP0039906B1 EP0039906B1 (en) | 1986-09-17 |
Family
ID=26846063
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP19810103455 Expired EP0039906B1 (en) | 1980-05-12 | 1981-05-07 | Aperture mask for a color television tube, color television tube comprising such a mask and method for obtaining the mask |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0039906B1 (en) |
JP (1) | JPH0713158Y2 (en) |
AR (1) | AR223591A1 (en) |
BR (1) | BR8102909A (en) |
CA (1) | CA1175876A (en) |
DE (1) | DE3175329D1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0715331A3 (en) * | 1990-11-22 | 1997-05-28 | Toshiba Kk | Negative plate used for manufacture of a shadow mask, and method for manufacturing the negative plate |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3973965A (en) * | 1972-05-30 | 1976-08-10 | Tokyo Shibaura Electric Co., Ltd. | Making shadow mask with slit-shaped apertures for CRT |
US4069085A (en) * | 1973-07-16 | 1978-01-17 | U.S. Philips Corporation | Apparatus for forming apertures in a thin metal tape such as a shadow mask for a color television display tube |
US4168450A (en) * | 1976-07-19 | 1979-09-18 | Hitachi, Ltd. | Slot type shadow mask |
GB2020892A (en) * | 1978-05-10 | 1979-11-21 | Rca Corp | C.R.T. Silt Type Shadow Mask |
GB2067827A (en) * | 1979-12-18 | 1981-07-30 | Rca Corp | Colour picture tube having slit type shadow mask |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4881762U (en) * | 1971-12-30 | 1973-10-05 | ||
US3916243A (en) * | 1974-09-20 | 1975-10-28 | Buckbee Mears Co | Channeled shadow mask |
-
1981
- 1981-04-29 CA CA000376484A patent/CA1175876A/en not_active Expired
- 1981-05-05 AR AR28520981A patent/AR223591A1/en active
- 1981-05-07 EP EP19810103455 patent/EP0039906B1/en not_active Expired
- 1981-05-07 DE DE8181103455T patent/DE3175329D1/en not_active Expired
- 1981-05-11 BR BR8102909A patent/BR8102909A/en unknown
-
1992
- 1992-03-09 JP JP1992011637U patent/JPH0713158Y2/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3973965A (en) * | 1972-05-30 | 1976-08-10 | Tokyo Shibaura Electric Co., Ltd. | Making shadow mask with slit-shaped apertures for CRT |
US4069085A (en) * | 1973-07-16 | 1978-01-17 | U.S. Philips Corporation | Apparatus for forming apertures in a thin metal tape such as a shadow mask for a color television display tube |
US4168450A (en) * | 1976-07-19 | 1979-09-18 | Hitachi, Ltd. | Slot type shadow mask |
GB2020892A (en) * | 1978-05-10 | 1979-11-21 | Rca Corp | C.R.T. Silt Type Shadow Mask |
GB2067827A (en) * | 1979-12-18 | 1981-07-30 | Rca Corp | Colour picture tube having slit type shadow mask |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0715331A3 (en) * | 1990-11-22 | 1997-05-28 | Toshiba Kk | Negative plate used for manufacture of a shadow mask, and method for manufacturing the negative plate |
Also Published As
Publication number | Publication date |
---|---|
EP0039906A3 (en) | 1982-06-16 |
AR223591A1 (en) | 1981-08-31 |
BR8102909A (en) | 1982-02-02 |
EP0039906B1 (en) | 1986-09-17 |
JPH069043U (en) | 1994-02-04 |
DE3175329D1 (en) | 1986-10-23 |
CA1175876A (en) | 1984-10-09 |
JPH0713158Y2 (en) | 1995-03-29 |
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