US3574013A - Aperture mask for color tv picture tubes and method for making same - Google Patents

Aperture mask for color tv picture tubes and method for making same Download PDF

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Publication number
US3574013A
US3574013A US789264A US3574013DA US3574013A US 3574013 A US3574013 A US 3574013A US 789264 A US789264 A US 789264A US 3574013D A US3574013D A US 3574013DA US 3574013 A US3574013 A US 3574013A
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United States
Prior art keywords
mask
layer
openings
metal
aperture
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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.)
Expired - Lifetime
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US789264A
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English (en)
Inventor
John J Frantzen
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Buckbee Mears Co
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Buckbee Mears Co
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    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/07—Shadow masks
    • H01J2229/0727—Aperture plate
    • H01J2229/0777—Coatings
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S156/00—Adhesive bonding and miscellaneous chemical manufacture
    • Y10S156/918—Delaminating processes adapted for specified product, e.g. delaminating medical specimen slide
    • Y10S156/919—Delaminating in preparation for post processing recycling step
    • Y10S156/922—Specified electronic component delaminating in preparation for recycling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T156/00—Adhesive bonding and miscellaneous chemical manufacture
    • Y10T156/11—Methods of delaminating, per se; i.e., separating at bonding face

Definitions

  • This invention is involved generally with the fabrication and assembly of color TV picture tubes containing aperture masks and, in particular, is concerned with the manufacturing steps in which the aperture mask is first used to form the phosphor dot pattern on the face plate after which it is permanently attached inside the tube for normal operation.
  • the three primary color phosphor dots are formed on the inside surface of the glass face plate of a color TV picture tube using an aperture mask and after these dots have been formed the same mask is permanent- 1y attached in the tube to provide its normal function of directing the electron beams to strike the proper phosphor dots.
  • the permanently attached aperture mask contains openings which are somewhat larger than those in the same mask when it was used for forming the phosphor dots.
  • the aperture mask is formed in the conventional manner using photographic techniques to form a pattern in a protective coating of enamel over a sheet of metal and then etching out the holes to the largest usable size. Then, while the enamel is still in place, the holes are partially filled with a material different from the base metal.
  • This mask is then used for forming the phosphor dot pattern but before the mask is 3,574,013 Patented Apr. 6, I971 permanently installed in the tube the filling material is removed from the openings to return them to their original dimensions. While this scheme works in theory, there are practical limitations.
  • the enamel that remains has usually deteriorated sufficiently that it can no longer serve as an adequate protective coating.
  • the mask before the mask can be used to form the phosphor dot pattern, it must be shaped aspherically or domed which requires mechanical working and heat treating which would destroy the enamel coating. To fill the openings before the mask is domed is impractical because the shaping would alter the size and shape of the openings.
  • the base metal aperture mask is formed in the conventional manner, using photoprinting and chemical etching techniques, and is then shaped or domed with the enamel coating removed.
  • the openings in the mask are partially closed. After the phosphor dots have been formed on the face plate, the openings are enlarged back to their original size.
  • the mask is at least made double layered, one of the layers having smaller apertures. After the phosphor dots have been formed the smaller-opening layer is removed while the largeropening layer remains.
  • two separate aperture mask are made from the same matrix plate and formed on the same die but with one of these masks having somewhat smaller openings than the other.
  • the tWo masks are brought together in register for forming the phosphor dots but afterwards the mask with the smaller openings i removed and the larger-opening mask is installed permanently in the picture tube.
  • the base metal mask is coated with a material to partially close the openings after the mask has been domed and the coating material is stripped away after the phosphor dots are formed.
  • FIG. 1 is a somewhat functional partial cross-section view of the forward part of a color TV picture tube, great- 1y simplified, illustrating the arangement of the component parts with which the present invention is involved;
  • FIG. 2 is a somewhat enlarged, simplified, cross-sectional view of a portion of FIG. 1 illustrating an embodiment of the invention of a mask with a covering layer on one side partially closing the openings;
  • FIG. 3 is a view similar to FIG. 2 illustrating another embodiment of this invention having two separate masks in register.
  • the conventional color TV aperture mask picture tube has a glass face plate or viewing face 10 which is coated on its inside surface with a layer of phosphor dots 11 representing the three primary colors.
  • the phosphor dots are represented as a uniform layer 11, there being no intent to illustrate the dot pattern.
  • an aperture mask 12 ordinarily made out of a thin sheet of metal, such as stainless steel, for example, and containing a translucent area formed by a myriad of miniature openings or apertures through which the electron beams pass when traveling toward the face plate 10 to strike the layer of phosphor 11.
  • the electron guns which eject the electron beams are located at the rear of the picture tube within the funnel shaped glass closure 15.
  • Other component parts of the picture tube such as shields, deflecting plates or coils, mounting hardware for the aperture mask, etc. have been deleted to simplify the drawing since they do not constitute an essential part of the invention nor are they necessary to fully describe the present invention.
  • this process may involve initially coating the inside surface of the face plate 10 with a first primary color phosphor in a sensitized carrier and exposing this coating to a suitable source of energy, such as light, through an aperture mask 12. Where the light strikes, hardened spots of the first color phosphor are formed and the unhardened areas are then washed away and removed. This is followed by applying a layer of a second primary color phosphor in a suitably sensitized carrier and exposing the second layer to an energy source through the aperture mask 12 in the same manner as before.
  • a suitable source of energy such as light
  • the base mask 12 can be made using well-known photoprinting and chemical milling or etching techniques and process steps which are described in the prior art such as in the Electronics article, supra, or in Mears US. Patents 2,762,149 and 2,822,635 and other patents referenced therein and in what is now regarded as a conventional manner, but with some variations.
  • these process steps include coating a thin sheet of metal, such as .01 inch stainless steel, with a sensitized enamel or the like and then exposing the sensitized coating to a suitable light source through a plate containing an array of opaque and transparent areas including miniature dot-like areas defining the desired aperture pattern.
  • the plate is ordinarily a positive so that light will not strike those areas which are to form the openings in the metal sheet so that the sensitized coating will not harden in those areas and will be washed away after exposure by subsequent developing treatment.
  • the dot pattern is photoprinted similarly in register on both sides of the metal, with the dots on one side being somewhat smaller than their counterparts on the other side. But here the smaller dots are photoprinted on the other side using a negative plate which means that after exposure and developing the enamel coating will remain only in the dot areas and will be removed from all other areas.
  • layer 12a is plated on the side of mask layer 12 which contains the small enamel dot areas.
  • This can be done, for example, by using well-known electroforming techniques in which the metal layer 12 with the enamel is immersed in a suitable bath so that the side to be plated is facing an anode of suitable material and the other side being protected in some convenient fashion so it does not become plated over.
  • one of the preferred metals is zine because it has the necessary characteristics which enable it to withstand the subsequent processing operations that the plated metal must go through.
  • an essential characteristic of the plating metal is that it must not react with nor be attacked by the same chemical etchant which is used to etch out the holes in the base metal.
  • the thickness of the plating layer should be monitored because this thickness will affect the effective size of the mask opening. In those areas where the openings are to be closed up the most, the plating may be heavier or thicker.
  • the dimensions of the enamel dots on this side of the base metal must be chosen so that they will be optimum size for the operation of forming the phosphor dots.
  • the base metal layer 12 is then sprayed with a chemical etchant applied to its other side.
  • a chemical etchant applied to its other side. This is done in the conventional manner using, for example, ferric chloride having a suitable Baum, if the metal is steel, which is preferred.
  • the spray is applied and controlled until the apertures or openings 13 have been milled out to the desired dimensions.
  • the shapes of openings :13 illustrated in the figures are ideal. As a practical matter, however, the openings are made with a somewhat tapered effect so that they are larger on the unplated side of the metal base 12 than on the plated side.
  • the etchant used on the base metal does not attack nor react with the layer 12a but it does remove all of the underlying support for the small dots of enamel which define the small openings 14 on the plated side so that the openings now pass completely through both layers 12 and 12a.
  • the smallest dimension of apertures 13 is in the order of .016 inch diameter and the smallest dimension of openings 14 is in the order of .008 inch at the central area of the mask and may increase in a graded manner up to approximately .009 inch near the outer edges of the mask. Without getting into details, the graded hole sizes are necessary for properly forming the phosphor dots. After the openings have been made through the two layers, all the remaining traces of enamel are then removed in the conventional manner by applying a suitable hot caustic solution followed by cleaning and drying.
  • the mask 12 with its plating layer 12a is domed and otherwise processed in the conventional manner which involves annealing and roller-leveling as well as other process steps. These are steps 'With which those engaged in the field of making TV aperture masks are familiar and they do not constitute part of the present invention so are not set forth in any detail here. Suffice is to say that, as explained earlier, the plating material for layer 12a is chosen so that its characteristics will enable it to withstand the temperatures and the forces applied during these operations without changing substantially.
  • the double-layered mask is now in a form such that it can be used in the phosphor dot process. As stated earlier, this process is not a part of the present invention and the process steps are well-known in the art and are set forth in detail in a number of publications, supra.
  • the plating layer 12a is no longer needed and, as a matter of fact, if allowed to remain would reduce the brilliancy of the picture produced on the viewing face of the tube. Therefore, this layer is then stripped away. Preferably, this is done by using a suitable chemical etchant which will attack the material of layer 12a but will not have any substantial effect on the material of mask layer 12.
  • a suitable chemical etchant which will attack the material of layer 12a but will not have any substantial effect on the material of mask layer 12.
  • the particular steps which are used to remove the plating layer 12a are not critical and a suitable etchant having the necessary constituency and characteristics is a matter of choice and can ordinarily be selected by one of ordinary skill in the art.
  • the plating layer 12a must be removed without physically affecting the mask 12 so that it will retain its initial size, shape, hole locations, etc. With the layer 12a removed, the mask 12 is now ready for permanent installation in the picture tube to serve its normal function with the result that the picture produced at the viewing face of the tube will be in the order of more brilliant than is the case with smaller openings in the aperture mask.
  • aperture mask 12 can be combined initially with a separate mask 12b made in a number of ways.
  • the mask 12 containing the larger-sized apertures can be formed using the conventional photographic and chemical milling techniques which are so thoroughly known in the prior art.
  • the other mask 12b can be formed in an identical fashion but with smaller appertures 14 which would be the same size as the openings 14 in the embodiment shown in FIG. 2. These both must be made from the same master plate and control of the etching should be used to reduce the size of the apertures in the second mask. This is for the reason that the two must eventually be arranged in overlaying fashion, as shown in FIG. 3, with their respective openings in exact register with one another.
  • Another way of making the two masks is to first make mask 12 with larger openings using well-known electroplating or electroforming techniques. This involves electroplating on a die or matrix plate or other carrier member, a layer of metal containing the desired pattern of larger-sized apertures. This layer is then stripped off the carrier plate and another layer of metal is electroformed on the same carrier plate but this time the process is continued on for a slightly longer period of time so that the layer of metal is thicker and the openings are somewhat smaller than before. Since both masks would then have been made on the same die, their respective openings would have to fall exactly on center with one another.
  • the mask layer 12 initially can be made in the conventional manner using the well-known photographic and chemical milling techniques. This involves etching out apertures 13 from both sides of the base metal after both sides of the metal have been photoprinted with positive plates in exact register. After apertures 13 have been etched out, all the remaining enamel is then removed in the conventional manner. Afterwards, layer 12a is plated on the one side of base metal 12, such as by electroplating, and a layer of the same material may be plated on the other side without using enamel or the like to define the areas to be plated over.
  • the plating material may be deposited along the walls of the apertures 13 to partially close them up and the size of the openings may be more accurately controlled.
  • these openings range from about .008 inch diameter in the central area of the mask to approximately .009 inch diameter at the outer edges and this involves a multitude of tens of thousands of holes.
  • the outer layers are then stripped away in some convenient fashion, e.g., chemical etching such as described briefly above.
  • the plating preferably should be done while the mask is still fiat although it can be done after doming, etc., provided proper control of the plating process is maintained.
  • a mask for laying down a pattern of colored phosphor dots on the face plate of the tube and for later functioning as an aperture mask during normal operation of the tube comprising in combination:
  • said opaque layer is made out of metal dissimilar to said metallic sheet and is bonded to said metallic sheet by electroplating.
  • a method for making a mask useful for laying out color phosphor dot patterns and for functioning as an aperture mask in a completed color television picture tube comprising the steps of:
  • a method for making a mask useful for laying out phosphor dots and for normal operation as an aperture mask in a color television picture tube comprising the steps of:

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
  • ing And Chemical Polishing (AREA)
US789264A 1969-01-06 1969-01-06 Aperture mask for color tv picture tubes and method for making same Expired - Lifetime US3574013A (en)

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Application Number Priority Date Filing Date Title
US78926469A 1969-01-06 1969-01-06

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US789264A Expired - Lifetime US3574013A (en) 1969-01-06 1969-01-06 Aperture mask for color tv picture tubes and method for making same

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DE (1) DE1920735C3 (ja)
FR (1) FR2027822A1 (ja)
GB (1) GB1214425A (ja)
NL (1) NL6916303A (ja)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3738233A (en) * 1972-01-17 1973-06-12 Zenith Radio Corp Camera process for color tube screen printing
US3753663A (en) * 1969-08-15 1973-08-21 Zenith Radio Corp Blank for shadow mask for color television picture tube
US3770434A (en) * 1971-10-15 1973-11-06 Rca Corp Method for making an image screen structure for an apertured-mask cathode-ray tube using a mask having temporary apertures
US3922395A (en) * 1973-11-09 1975-11-25 Rca Corp Method for applying organic polymeric coating composition to ferrous-metal surfaces
US3922394A (en) * 1973-11-09 1975-11-25 Rca Corp Method for coating ferrous-metal mask for cathode-ray tube
US3962005A (en) * 1975-06-30 1976-06-08 Zenith Radio Corporation Method for etching shadow mask and regenerating etchant
US3973965A (en) * 1972-05-30 1976-08-10 Tokyo Shibaura Electric Co., Ltd. Making shadow mask with slit-shaped apertures for CRT
US4106976A (en) * 1976-03-08 1978-08-15 International Business Machines Corporation Ink jet nozzle method of manufacture
US4353948A (en) * 1980-05-12 1982-10-12 Buckbee-Mears Company Hole technology
US4392914A (en) * 1981-09-10 1983-07-12 Tokyo Shibaura Denki Kabushiki Kaisha Method for manufacturing mask for color CRT
US4478589A (en) * 1981-09-02 1984-10-23 Tokyo Shibaura Denki Kabushiki Kaisha Method of shadow mask manufacture
US4482334A (en) * 1981-09-10 1984-11-13 Tokyo Shibaura Denki Kabushiki Kaisha Method for making CRT shadow masks
US4626737A (en) * 1981-02-25 1986-12-02 Tokyo Shibaura Denki Kabushiki Kaisha Mask focusing color picture tube
US4632726A (en) * 1984-07-13 1986-12-30 Bmc Industries, Inc. Multi-graded aperture mask method
AU582581B2 (en) * 1984-10-15 1989-04-06 At & T Teletype Corporation Silicon nozzle structures and method of manufacture
US5863681A (en) * 1996-09-19 1999-01-26 Wickeder Westgalenstahl Gmbh Composite shadow mask
US6255775B1 (en) * 1997-05-15 2001-07-03 Nec Corporation Shadow mask, a method of manufacturing a color thin film electroluminescent display apparatus using the shadow mask, and a color thin film electroluminescent display apparatus

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3753663A (en) * 1969-08-15 1973-08-21 Zenith Radio Corp Blank for shadow mask for color television picture tube
US3770434A (en) * 1971-10-15 1973-11-06 Rca Corp Method for making an image screen structure for an apertured-mask cathode-ray tube using a mask having temporary apertures
US3738233A (en) * 1972-01-17 1973-06-12 Zenith Radio Corp Camera process for color tube screen printing
US3973965A (en) * 1972-05-30 1976-08-10 Tokyo Shibaura Electric Co., Ltd. Making shadow mask with slit-shaped apertures for CRT
US3922395A (en) * 1973-11-09 1975-11-25 Rca Corp Method for applying organic polymeric coating composition to ferrous-metal surfaces
US3922394A (en) * 1973-11-09 1975-11-25 Rca Corp Method for coating ferrous-metal mask for cathode-ray tube
US3962005A (en) * 1975-06-30 1976-06-08 Zenith Radio Corporation Method for etching shadow mask and regenerating etchant
US4106976A (en) * 1976-03-08 1978-08-15 International Business Machines Corporation Ink jet nozzle method of manufacture
US4353948A (en) * 1980-05-12 1982-10-12 Buckbee-Mears Company Hole technology
US4626737A (en) * 1981-02-25 1986-12-02 Tokyo Shibaura Denki Kabushiki Kaisha Mask focusing color picture tube
US4478589A (en) * 1981-09-02 1984-10-23 Tokyo Shibaura Denki Kabushiki Kaisha Method of shadow mask manufacture
US4392914A (en) * 1981-09-10 1983-07-12 Tokyo Shibaura Denki Kabushiki Kaisha Method for manufacturing mask for color CRT
US4482334A (en) * 1981-09-10 1984-11-13 Tokyo Shibaura Denki Kabushiki Kaisha Method for making CRT shadow masks
US4632726A (en) * 1984-07-13 1986-12-30 Bmc Industries, Inc. Multi-graded aperture mask method
AU582581B2 (en) * 1984-10-15 1989-04-06 At & T Teletype Corporation Silicon nozzle structures and method of manufacture
US5863681A (en) * 1996-09-19 1999-01-26 Wickeder Westgalenstahl Gmbh Composite shadow mask
US6255775B1 (en) * 1997-05-15 2001-07-03 Nec Corporation Shadow mask, a method of manufacturing a color thin film electroluminescent display apparatus using the shadow mask, and a color thin film electroluminescent display apparatus

Also Published As

Publication number Publication date
NL6916303A (ja) 1970-07-08
GB1214425A (en) 1970-12-02
DE1920735A1 (de) 1970-09-17
DE1920735C3 (de) 1979-01-25
FR2027822A1 (ja) 1970-10-02
USB789264I5 (ja)
DE1920735B2 (de) 1978-05-24

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