CA1047377A - Etching process for accurately making small holes in thick materials - Google Patents
Etching process for accurately making small holes in thick materialsInfo
- Publication number
- CA1047377A CA1047377A CA209,902A CA209902A CA1047377A CA 1047377 A CA1047377 A CA 1047377A CA 209902 A CA209902 A CA 209902A CA 1047377 A CA1047377 A CA 1047377A
- Authority
- CA
- Canada
- Prior art keywords
- web
- dimension
- etching
- region
- thickness
- 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.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F1/00—Etching metallic material by chemical means
- C23F1/02—Local etching
-
- 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
- H01J2209/00—Apparatus and processes for manufacture of discharge tubes
- H01J2209/01—Generalised techniques
- H01J2209/012—Coating
- H01J2209/015—Machines therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- ing And Chemical Polishing (AREA)
Abstract
Abstract A sheet of metallic material in web form having a thick-ness T is partially covered on opposite sides by an etchant resist.
The sheet of material is then etched partially from both sides which is followed by applying a protective layer to one side of the sheet. Next, the side opposite the protective layer is etched until the sheet is etched through.
The sheet of material is then etched partially from both sides which is followed by applying a protective layer to one side of the sheet. Next, the side opposite the protective layer is etched until the sheet is etched through.
Description
3~'~
This invention generally relates to making small openings or slots in shadow masks ~or colored television tubes, more specifically, this is an etching process for producing accurate holes or openings in a continuous sheet or web of material in which the openings have a dimension smaller than the thickness of the material by utilizing a protective coating between the initial and final etching of the article.
In a colored television picture tube a shadow mask or aperture mask is located between electron guns at the rear of the tube and the phosphor faceplate on the face of the tube. Electron beams pass through tiny openings or apertures in the shadow mask and impinge upon a suitable color producing phosphor dot on the faceplate. Located in line with the openings of the shadow mask are three phosphor dots, a triad, one dot for each of the three primary colors. During the operation of the picture tube, the shadow mask opening acts as a guide for the electron beams.
Thus, one of the uses of the present invention is a process for making a shadow mask for a television tube which requires the formation of aper-tures on an intermittently moving web.
The problem of making small holes or apertures in thicker materials is that it is difficult if not impossible to accurately etch an opening which has a minimum dimension less than the thickness of the material unless some special procedures are used. That is, the con-ventional etching techniquesr i.e., etching from both sides produces over-etching as well as irregular etching. The over-etching is produced by lateral etching of the material that inherently accompanies etching perpendicular to the surface of the material. Consequently, the process of accurately making holes having a minimum dimension of less than the thickness of the material is a difficult and time consuming task. The task is even more difficult when applied to a continuous production of -. 1 ~ .
. ~ :
, .: .
~7;37~
etched material in web form. An example of a prior art process for etching a single opening in a thick material is shown in United States Mears et al patent 2,~37,228 where a small opening is etched to a depth of .002~1 to .010 inches while the opposite side is protec~ed. Then a protective coat-ing of asphaltum or other resis~ is filled in the opening and the opposite side of the article is etched until the plugs of asphaltum show through.
Thus, the present invention comprises a process for continuously -and accurately etching openings which have a minimum dimension less than the thickness of the material being etched. Although the present invention is specifically for the problem of etching openings having a dimension less than the material, it is apparent that it can also be used for etching dimensions greater than the thickness of the material. However, its greatest contri-bution is that the process can enable one to accurately etch openings having dimensions less than the thickness of the material on a continuous or intermittently moving web of material.
According to the present invention, there is provided a process of accurately etching an opening which has a minimum dimension that is less than the thickness of the article comprising:
applying a first layer of etchant resist on one side of a web having ~, 20 a thickness T;
applying a second layer of etchant resist on the opposite side of the web, with said first layer of etchant resist having a first unprotected region of dimension Xl, said second layer of etchant resist having a second mprotected region of dimension X2 with X2 being substantially larger than X
.~ 1' subjecting said web to etching from both sides until a dished out region is produced on the first unprotected region of the web and on the second ~ unprotected region located on the opposite side of said web and until the ^~ unetched portion located between the dished out region located in the first . . .
-~ 30 unprotected region and the dished out region located in the second unprotected region has a dimension H, said unetched portion dimension H ranging from about 20% *o ~0% of the thickness of said web;
This invention generally relates to making small openings or slots in shadow masks ~or colored television tubes, more specifically, this is an etching process for producing accurate holes or openings in a continuous sheet or web of material in which the openings have a dimension smaller than the thickness of the material by utilizing a protective coating between the initial and final etching of the article.
In a colored television picture tube a shadow mask or aperture mask is located between electron guns at the rear of the tube and the phosphor faceplate on the face of the tube. Electron beams pass through tiny openings or apertures in the shadow mask and impinge upon a suitable color producing phosphor dot on the faceplate. Located in line with the openings of the shadow mask are three phosphor dots, a triad, one dot for each of the three primary colors. During the operation of the picture tube, the shadow mask opening acts as a guide for the electron beams.
Thus, one of the uses of the present invention is a process for making a shadow mask for a television tube which requires the formation of aper-tures on an intermittently moving web.
The problem of making small holes or apertures in thicker materials is that it is difficult if not impossible to accurately etch an opening which has a minimum dimension less than the thickness of the material unless some special procedures are used. That is, the con-ventional etching techniquesr i.e., etching from both sides produces over-etching as well as irregular etching. The over-etching is produced by lateral etching of the material that inherently accompanies etching perpendicular to the surface of the material. Consequently, the process of accurately making holes having a minimum dimension of less than the thickness of the material is a difficult and time consuming task. The task is even more difficult when applied to a continuous production of -. 1 ~ .
. ~ :
, .: .
~7;37~
etched material in web form. An example of a prior art process for etching a single opening in a thick material is shown in United States Mears et al patent 2,~37,228 where a small opening is etched to a depth of .002~1 to .010 inches while the opposite side is protec~ed. Then a protective coat-ing of asphaltum or other resis~ is filled in the opening and the opposite side of the article is etched until the plugs of asphaltum show through.
Thus, the present invention comprises a process for continuously -and accurately etching openings which have a minimum dimension less than the thickness of the material being etched. Although the present invention is specifically for the problem of etching openings having a dimension less than the material, it is apparent that it can also be used for etching dimensions greater than the thickness of the material. However, its greatest contri-bution is that the process can enable one to accurately etch openings having dimensions less than the thickness of the material on a continuous or intermittently moving web of material.
According to the present invention, there is provided a process of accurately etching an opening which has a minimum dimension that is less than the thickness of the article comprising:
applying a first layer of etchant resist on one side of a web having ~, 20 a thickness T;
applying a second layer of etchant resist on the opposite side of the web, with said first layer of etchant resist having a first unprotected region of dimension Xl, said second layer of etchant resist having a second mprotected region of dimension X2 with X2 being substantially larger than X
.~ 1' subjecting said web to etching from both sides until a dished out region is produced on the first unprotected region of the web and on the second ~ unprotected region located on the opposite side of said web and until the ^~ unetched portion located between the dished out region located in the first . . .
-~ 30 unprotected region and the dished out region located in the second unprotected region has a dimension H, said unetched portion dimension H ranging from about 20% *o ~0% of the thickness of said web;
- 2 -. .
3~
then applying a resist coating on top of the resist layer and into the dished out opening of dimension Xl; and then etching on the side of the web having the dimension designated by X2, said etching removing sufficient material to produce a thinning of the web in the region of the web opposite the unprotected region of dimension Xl until an opening having a minimum final dimension less than the thickness T is etched through the web.
Thus, the present invention comprises a process where a web is partially etched from both sides. A protecting coating is then applied on one side of the web. Next, the unprotected side of the web is etched for a predetermined time to provide an accurate opening in the central portion of the web.
A particlar embodiment of-the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:
Fig. 1 shows in schematic form an etching system of the present ln-vention; and Fig. 2 shows an enlarged sectional view of the appearance of the web as it is ready to undergo the final stages of etching.
Referring ~o the drawing, reference numerals 11, 12, 13, 14, 15 and 16 all designate different types of chambers in the etching system. Reference numeral 11 designates an etching chamber - 2a -having upper spray nozzles 19 a~d lower spray nozzles 20. Re~erence numeral 12 designates a station having spray nozzles 21 and 22 therein. Re~erence numeral 13 designates a heating or drying station having heating elements 23 and 24 therein and re~erence numeral 14 designates a spray coating station having spray nozzles 25 therein. Located immediately after coating station 14 is a drying station 15 having heating elements 26 and 27 therein~ The last station in the etching system is a spray etching station 16 having a set of spray nozzles 28 ~or spraying etchant on a travel-ing web 9. Traveling web 9 passes through the chambers around aroller 30, between a pair o~ rollers 31 and onto a larger take-up roller 32.
Referring to Figr 2, an enlarged cross sectional view o~ web 9 is shown having thickness designated To Located on the top side o~ web 9 is a resist layer 42 and located on the bottom side is a resist layer 44. Located on top o~ resist layer 42 is a shield or coating 43 which is applied at station 14. The dimen-sions of the opening in resist layer 42 are designated Xl and the dimens~on o~ the opening in resist layer 44 is designa-ted by X2.
The article has a central unetched portion o~ dimension H. By controlling the time and temperature o-f the etching solution, the portion o~ the article designated by thickness H can be le~t to be etched i~ a later step.
In the process o~ $he present invention a web 9 having an etchant resist pattern on both sides o~ the web is subjected to spray etching ~rom above by no~zles 19 and ~rom below by nozzles 20 which are located in etching chamber 11. In order to etch to the proper depth, the time and temperature o~ the etchan-t are controlled. A~ter a predetermined time the etchant spray is re-moved khus leaving the article having recesses on opposite sideso~ the web. Typically, with a material having a thickness T o~
.006" the unetched central dimension ~ is about .002". A~ter :: , :
?~) etching both sides of web 9 the web enters station 12 where the web is rinsed to remove any etchant adhering to the web. Next, the web is dried by heatexs 23 and 24 which are located in station 13. Next, a protective resist is applied or sprayed on the side of the web having the smaller opening designated by Xl. The spray coating is then dried in station 15 by heaters 26 and 27.
Typical coating materials are paraffin or the like, however, polymer plastics that are resistant to the etchant are also suitable.
Next, the wèb 9 having the larger opening denoted by X2 is etched in etching chamber lS by a set of spray nozzles 28 that direct etchant vertically upward to impinge against the recess region located beneath resist 44. The time and temperature of the etchant axe controlled so the final dimension H is etched .
completely through. By etching from the side having the larger opening, one produces an opening in the article which corresponds to the opening Xl in resist layer 42.
Thus~ it is apparent the present process provides a method for accurateIy e~ching openings which have a minimum dimension which is as small as 4.0% of the:thickness of the material . T.
-.~ , . ~ . . ' .
then applying a resist coating on top of the resist layer and into the dished out opening of dimension Xl; and then etching on the side of the web having the dimension designated by X2, said etching removing sufficient material to produce a thinning of the web in the region of the web opposite the unprotected region of dimension Xl until an opening having a minimum final dimension less than the thickness T is etched through the web.
Thus, the present invention comprises a process where a web is partially etched from both sides. A protecting coating is then applied on one side of the web. Next, the unprotected side of the web is etched for a predetermined time to provide an accurate opening in the central portion of the web.
A particlar embodiment of-the present invention will now be described by way of example only, with reference to the accompanying drawings, in which:
Fig. 1 shows in schematic form an etching system of the present ln-vention; and Fig. 2 shows an enlarged sectional view of the appearance of the web as it is ready to undergo the final stages of etching.
Referring ~o the drawing, reference numerals 11, 12, 13, 14, 15 and 16 all designate different types of chambers in the etching system. Reference numeral 11 designates an etching chamber - 2a -having upper spray nozzles 19 a~d lower spray nozzles 20. Re~erence numeral 12 designates a station having spray nozzles 21 and 22 therein. Re~erence numeral 13 designates a heating or drying station having heating elements 23 and 24 therein and re~erence numeral 14 designates a spray coating station having spray nozzles 25 therein. Located immediately after coating station 14 is a drying station 15 having heating elements 26 and 27 therein~ The last station in the etching system is a spray etching station 16 having a set of spray nozzles 28 ~or spraying etchant on a travel-ing web 9. Traveling web 9 passes through the chambers around aroller 30, between a pair o~ rollers 31 and onto a larger take-up roller 32.
Referring to Figr 2, an enlarged cross sectional view o~ web 9 is shown having thickness designated To Located on the top side o~ web 9 is a resist layer 42 and located on the bottom side is a resist layer 44. Located on top o~ resist layer 42 is a shield or coating 43 which is applied at station 14. The dimen-sions of the opening in resist layer 42 are designated Xl and the dimens~on o~ the opening in resist layer 44 is designa-ted by X2.
The article has a central unetched portion o~ dimension H. By controlling the time and temperature o-f the etching solution, the portion o~ the article designated by thickness H can be le~t to be etched i~ a later step.
In the process o~ $he present invention a web 9 having an etchant resist pattern on both sides o~ the web is subjected to spray etching ~rom above by no~zles 19 and ~rom below by nozzles 20 which are located in etching chamber 11. In order to etch to the proper depth, the time and temperature o~ the etchan-t are controlled. A~ter a predetermined time the etchant spray is re-moved khus leaving the article having recesses on opposite sideso~ the web. Typically, with a material having a thickness T o~
.006" the unetched central dimension ~ is about .002". A~ter :: , :
?~) etching both sides of web 9 the web enters station 12 where the web is rinsed to remove any etchant adhering to the web. Next, the web is dried by heatexs 23 and 24 which are located in station 13. Next, a protective resist is applied or sprayed on the side of the web having the smaller opening designated by Xl. The spray coating is then dried in station 15 by heaters 26 and 27.
Typical coating materials are paraffin or the like, however, polymer plastics that are resistant to the etchant are also suitable.
Next, the wèb 9 having the larger opening denoted by X2 is etched in etching chamber lS by a set of spray nozzles 28 that direct etchant vertically upward to impinge against the recess region located beneath resist 44. The time and temperature of the etchant axe controlled so the final dimension H is etched .
completely through. By etching from the side having the larger opening, one produces an opening in the article which corresponds to the opening Xl in resist layer 42.
Thus~ it is apparent the present process provides a method for accurateIy e~ching openings which have a minimum dimension which is as small as 4.0% of the:thickness of the material . T.
-.~ , . ~ . . ' .
Claims
1. The process of accurately etching an opening which has a minimum dimension that is less than the thickness of the article comprising:
applying a first layer of etchant resist on one side of a web having a thickness T;
applying a second layer of etchant resist on the opposite side of the web, with said first layer of etchant resist having a first unprotected region of dimension X1, said second layer of etchant resist having a second unprotected region of dimension X2 with X2 being substantially larger than X1;
subjecting said web to etching from both sides until a dished out region is produced on the first unprotected region of the web and on the second un-protected region located on the opposite side of said web and until the unetched portion located between the dished out region located in the first unprotected region and the dished out region located in the second unprotected region has a dimension H, said unetched portion dimension H ranging from about 20% to 40% of the thickness of said web;
then applying a resist coating on top of the resist layer and into the dished out opening of dimension X1; and then etching on the side of the web having the dimension designated by X2, said etching removing sufficient material to produce a thinning of the web in the region of the web opposite the unprotected region of dimension X1 until an opening having a mini-mum final dimension less than the thickness T is etched through the web.
applying a first layer of etchant resist on one side of a web having a thickness T;
applying a second layer of etchant resist on the opposite side of the web, with said first layer of etchant resist having a first unprotected region of dimension X1, said second layer of etchant resist having a second unprotected region of dimension X2 with X2 being substantially larger than X1;
subjecting said web to etching from both sides until a dished out region is produced on the first unprotected region of the web and on the second un-protected region located on the opposite side of said web and until the unetched portion located between the dished out region located in the first unprotected region and the dished out region located in the second unprotected region has a dimension H, said unetched portion dimension H ranging from about 20% to 40% of the thickness of said web;
then applying a resist coating on top of the resist layer and into the dished out opening of dimension X1; and then etching on the side of the web having the dimension designated by X2, said etching removing sufficient material to produce a thinning of the web in the region of the web opposite the unprotected region of dimension X1 until an opening having a mini-mum final dimension less than the thickness T is etched through the web.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US48766374A | 1974-07-11 | 1974-07-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047377A true CA1047377A (en) | 1979-01-30 |
Family
ID=23936650
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA209,902A Expired CA1047377A (en) | 1974-07-11 | 1974-09-24 | Etching process for accurately making small holes in thick materials |
Country Status (9)
| Country | Link |
|---|---|
| JP (1) | JPS519034A (en) |
| BE (1) | BE820732A (en) |
| BR (1) | BR7410019A (en) |
| CA (1) | CA1047377A (en) |
| DE (1) | DE2446781A1 (en) |
| FR (1) | FR2278150A1 (en) |
| GB (1) | GB1468298A (en) |
| IT (1) | IT1022731B (en) |
| NL (1) | NL7412740A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES8504247A1 (en) * | 1982-10-06 | 1985-04-01 | Novo Industri As | Method for production of an immobilized enzyme preparation by means of a crosslinking agent |
| JPS6070185A (en) * | 1983-09-26 | 1985-04-20 | Toshiba Corp | Production of shadow mask |
| JPS6160889A (en) * | 1984-08-30 | 1986-03-28 | Toshiba Corp | Production of shadow mask |
| JPH0522346U (en) * | 1991-09-05 | 1993-03-23 | 東洋紡績株式会社 | Labeled container |
| CN110699637B (en) * | 2019-10-17 | 2021-03-23 | 昆山国显光电有限公司 | Mask manufacturing method, mask and display panel manufacturing method |
-
1974
- 1974-09-20 GB GB4098874A patent/GB1468298A/en not_active Expired
- 1974-09-24 CA CA209,902A patent/CA1047377A/en not_active Expired
- 1974-09-26 NL NL7412740A patent/NL7412740A/en not_active Application Discontinuation
- 1974-10-01 DE DE19742446781 patent/DE2446781A1/en not_active Ceased
- 1974-10-04 BE BE149238A patent/BE820732A/en unknown
- 1974-10-09 IT IT2823574A patent/IT1022731B/en active
- 1974-10-29 FR FR7436135A patent/FR2278150A1/en active Granted
- 1974-11-29 BR BR1001974A patent/BR7410019A/en unknown
- 1974-12-27 JP JP14910874A patent/JPS519034A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB1468298A (en) | 1977-03-23 |
| BR7410019A (en) | 1976-05-25 |
| FR2278150A1 (en) | 1976-02-06 |
| JPS519034A (en) | 1976-01-24 |
| FR2278150B1 (en) | 1978-09-22 |
| DE2446781A1 (en) | 1976-01-29 |
| JPS5726345B2 (en) | 1982-06-03 |
| NL7412740A (en) | 1976-01-13 |
| IT1022731B (en) | 1978-04-20 |
| BE820732A (en) | 1975-02-03 |
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