EP0522273A1 - Shadow mask for picture tubes - Google Patents
Shadow mask for picture tubes Download PDFInfo
- Publication number
- EP0522273A1 EP0522273A1 EP92108830A EP92108830A EP0522273A1 EP 0522273 A1 EP0522273 A1 EP 0522273A1 EP 92108830 A EP92108830 A EP 92108830A EP 92108830 A EP92108830 A EP 92108830A EP 0522273 A1 EP0522273 A1 EP 0522273A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- heavy metal
- mask
- shadow mask
- shadow
- protective coating
- 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.)
- Withdrawn
Links
Classifications
-
- 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
- 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
- H01J9/146—Surface treatment, e.g. blackening, coating
-
- 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
Definitions
- the invention is concerned with the coating of shadow masks for picture tubes.
- Shadow masks have long been known in the prior art, so that in this context, a more detailed explanation of their structure and mode of operation can be dispensed with. For a better understanding, however, the following two points should be emphasized: One point is that shadow masks have a plurality of round or elongated openings through which the electrons emitted by the electron generating system pass on their way to the luminescent screen. The other - particularly noteworthy - point concerns the structure of the shadow mask. Shadow masks usually have a protective coating on the side facing the electron gun system. This protective cover has the task that not by the Openings of the shadow mask passing through, but reflecting on the surface of the electrons.
- Heavy metal oxides are used as materials which cause the reflection of the incident electrons. These heavy metal oxides, which must have a high level of purity for the formation of the protective layer, are usually ground very finely, dispersed in a distribution medium and sprayed as a suspension onto the mask surface to be coated.
- the invention is therefore based on the object of specifying a protective coating for shadow masks of picture tubes which prevents the shadow mask from being heated by impinging electrons.
- Another object of the invention is to provide a method for producing protective coatings for shadow masks, which is simplified compared to the spraying method described above.
- the initially named object is achieved according to the teaching specified in claim 1 in that the shadow mask is provided at least on the side facing the electron gun with a uniformly thick protective coating which is formed from pure metallic heavy metal.
- the effect of the mask designed according to the invention is due to the fact that only a metallically pure heavy metal coating ensures the uniform and continuous coating of the mask required for complete reflection of the incident electrons.
- the result of the device according to the invention could also be achieved with masks which are coated with a heavy metal oxide if it were ensured that the heavy metal oxides can be distributed so closely on the mask that the heavy metal oxide grains would lie close to one another, that is to say virtually without a joint.
- a formation of the protective layer would require a grain size of the heavy metal oxide particles of less than 0.5 ⁇ m. The very last requirement alone should significantly increase the difficulties that already arise with the conventionally known procedure.
- the mask is designed according to claim 1, this has the further advantage that it also improves the thermal behavior of the mask. This is because the metallic heavy metal layer is significantly darker than the protective layer formed from heavy metal oxide and therefore also radiates the heat better.
- the second object is achieved according to claim 4 in that the shadow mask is coated electrochemically. This procedure alone allows a consistently uniform heavy metal protective layer in large quantities with an inexpensive design. The cost comparison is primarily drawn for the vapor deposition of heavy metal layers.
- the metallic protective layer with an alkali silicate layer for example one Coated with a sodium silicate layer, this has the advantage that the metallic heavy metal does not drip in subsequent operations which heat the mask above the melting temperature of the heavy metal.
- the alkali silicate layer has the effect that the adhesion of the heavy metal to the mask surface is improved when the mask is exposed to temperature.
- the metallic heavy metal is electrolessly deposited on the mask surface, this has the advantage over electrolytic deposition that there are no differences in the thickness of the heavy metal layer in comparison between the mask edge and the center of the mask. According to the applicant's knowledge, these differences in the layer thickness during electrolytic deposition can be attributed to the fact that a field line concentration occurs at the edge of the mask opposite the center of the mask, which in turn is responsible for a stronger metal deposition in the peripheral regions of the mask. In addition to the different thickness of the heavy metal layer between the edge of the mask and the center of the mask, the mask holes on the edge are also reduced by the increased heavy metal deposition.
- heavy metal oxide is first dissolved in a suitable acid in a bath.
- This acid can be nitric acid for bismuth oxide, for example.
- Electroless plating takes place only when the metal from which the shadow mask is made is less noble than the metal that forms the protective coating. Whether a metal is more noble than another metal is assessed by comparing the electronegativity of the metals to be assessed. In general it can be said that with increasing electronegativity the metal becomes less noble. If, in the present exemplary embodiment, the shadow mask is made of iron and if this mask is to be provided with a bismuth coating, there is a sufficiently large difference in electronegativity between iron and bismuth so that bismuth can be deposited without current on the shadow mask.
- the mask If the mask has reacted in the bath for a sufficiently long time, because iron has dissolved out of the mask and, for example, bismuth has deposited from the solution on the surface of the mask, the mask is removed from the bath.
- the coated mask can be applied after a Washing process can be used in another bath containing an alkali silicate solution, for example in the form of a sodium silicate solution. If the mask is then removed from the bath described last and the sodium silicate solution adhering to its surface is dried, the temperature resistance of the heavy metal protective layer is increased. In particular, metallic heavy metal is prevented from dripping if the mask is heated beyond the melting point of the heavy metal in subsequent processing steps. In addition, it is pointed out that if the mask is immersed in an alkali silicate bath, the procedure must be such that damage to the mask is also avoided here.
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Electrodes For Cathode-Ray Tubes (AREA)
Abstract
Description
Die Erfindung befaßt sich mit der Beschichtung von Schattenmasken für Bildröhren.The invention is concerned with the coating of shadow masks for picture tubes.
Derartige Schattenmasken sind seit langem im Stand der Technik bekannt, so daß in diesem Zusammenhang auf eine nähere Erläuterung ihres Aufbaus und ihrer Funktionsweise verzichtet werden kann.
Zum besseren Verständnis seien jedoch folgende zwei Punkte besonders ausgeführt:
Der eine Punkt ist der, daß Schattenmasken über eine Vielzahl von runden oder länglich ausgebildeten Öffnungen verfügen, die die vom Elektronenerzeugersystem emittierten Elektronen auf ihrem Weg zum Leuchtschirm hin passieren. Der weitere - besonders erwähnenswerte - Punkt betrifft den Aufbau der Schattenmaske. Üblicherweise weisen Schattenmasken auf der dem Elektronenstrahlerzeugersystem zugewandten Seite einen Schutzüberzug auf. Dieser Schutzüberzug hat die Aufgabe, die nicht durch die Öffnungen der Schattenmaske hindurchtretenden, sondern auf deren Oberfläche auftreffenden Elektronen zu reflektieren. Dies ist deshalb erforderlich, weil sich sonst, wenn die Elektronen direkt, d. h. ohne Anordnung eine Schutzüberzugs auf die Schattenmaskenoberfläche auftreffen, die Oberfläche der Maske an denjenigen Auftreffstellen erwärmt und durch das Vorhandensein von durch Elektronenbeschuß erwärmten und nicht erwärmten Maskengebieten innerhalb der Maske Spannungen auftreten, die die Maskenstruktur verzerren und dadurch die Farbreinheit der Bildröhre beeinträchtigen.Such shadow masks have long been known in the prior art, so that in this context, a more detailed explanation of their structure and mode of operation can be dispensed with.
For a better understanding, however, the following two points should be emphasized:
One point is that shadow masks have a plurality of round or elongated openings through which the electrons emitted by the electron generating system pass on their way to the luminescent screen. The other - particularly noteworthy - point concerns the structure of the shadow mask. Shadow masks usually have a protective coating on the side facing the electron gun system. This protective cover has the task that not by the Openings of the shadow mask passing through, but reflecting on the surface of the electrons. This is necessary because otherwise, if the electrons strike the shadow mask surface directly, ie without a protective coating, the surface of the mask heats up at those points of impact and voltages occur within the mask due to the presence of mask areas heated and not heated by electron bombardment. that distort the mask structure and thereby impair the color purity of the picture tube.
Als Materialien, welche die Reflektion der auftreffenden Elektronen bewirken, werden Schwermetalloxide verwendet. Üblicherweise werden diese Schwermetalloxide, welche für die Schutzschichtausbildung eine große Reinheit aufweisen müssen, sehr fein vermahlen, in einem Verteilungsmittel dispergiert und als Suspension auf die zu beschichtende Maskenoberfläche aufgesprüht.Heavy metal oxides are used as materials which cause the reflection of the incident electrons. These heavy metal oxides, which must have a high level of purity for the formation of the protective layer, are usually ground very finely, dispersed in a distribution medium and sprayed as a suspension onto the mask surface to be coated.
Obwohl eine derartig ausgebildete Schutzschicht die auftreffenden Elektronen weitgehend reflektiert, kann die verbleibende Erwärmung der Maske durch die nicht reflektierten Elektronen noch so groß sein, daß Spannungen in der Maske die Farbreinheit der Bildröhre beeinträchtigen.Although a protective layer formed in this way largely reflects the incident electrons, the remaining heating of the mask by the non-reflected electrons can be so great that voltages in the mask impair the color purity of the picture tube.
Außerdem wird in der Praxis die Beschichtung der Maskenoberfläche mit einer Schwermetalloxidsuspension in Sprühtechnik als nachteilig angesehen. Dies deshalb, weil das Schwermetalloxid eine hohe Reinheit aufweisen muß und bis zu einer Korngröße von etwa 0,5 bis etwa 0,8 um gemahlen werden muß. Des weiteren neigt die Schwermetalloxidsuspension zur Sedimentation und Konglomeration, so daß die Suspension ständig ungepumpt und filtriert werden muß.In addition, coating the mask surface with a heavy metal oxide suspension using spray technology is considered disadvantageous in practice. This is because the heavy metal oxide must be of high purity and ground to a grain size of about 0.5 to about 0.8 µm. Furthermore, the heavy metal oxide suspension tends to sedimentation and conglomeration, so that the suspension is constantly unpumped and must be filtered.
Daher liegt der Erfindung die Aufgabe zugrunde, einen Schutzüberzug für Schattenmasken von Bildröhren anzugeben, welcher eine Erwärmung der Schattenmaske durch auftreffende Elektronen ausschließt. Weitere Aufgabe der Erfindung ist es, ein Verfahren zur Herstellung von Schutzüberzügen für Schattenmasken anzugeben, welches gegenüber den oben beschriebenen Spritzverfahren vereinfacht ist.The invention is therefore based on the object of specifying a protective coating for shadow masks of picture tubes which prevents the shadow mask from being heated by impinging electrons. Another object of the invention is to provide a method for producing protective coatings for shadow masks, which is simplified compared to the spraying method described above.
Die zunächst benannte Aufgabe wird gemäß der im Anspruch 1 angegebenen Lehre dadurch gelöst, daß die Schattenmaske zumindest auf der Seite, die dem Elektronenstrahlerzeugungssystem zugewandt ist, durchgängig mit einem gleichmäßig dicken Schutzüberzug versehen ist, der aus metallisch reinem Schwermetall gebildet ist.The initially named object is achieved according to the teaching specified in claim 1 in that the shadow mask is provided at least on the side facing the electron gun with a uniformly thick protective coating which is formed from pure metallic heavy metal.
Die, die Erwärmung der Schattenmaske ausschließende Wirkung der erfindungsgemäß ausgebildeten Maske ist nach Erkenntnissen der Anmelderin darauf zurückzuführen, daß erst ein metallisch reiner Schwermetallüberzug die für eine vollständige Reflektion der auftreffende Elektronen erforderliche gleichmäßige und durchgängige Beschichtung der Maske gewährleistet. Theoretisch wäre das Ergebnis der erfindungsgemäßen Vorrichtung auch mit Masken erzielbar, die mit einem Schwermetalloxid beschichtet sind, wenn gewährleistet wäre, daß die Schwermetalloxide so eng auf der Maske verteilt werden können, daß die Schwermetalloxidkörnchen dicht an dicht, also quasi fugenlos aneinander liegen würden. Abgesehen davon, daß die zuletzt aufgestellte Forderung nicht erreicht werden kann, würde eine derartige Ausbildung der Schutzschicht eine Korngröße der Schwermetalloxidpartikel von kleiner 0,5 um erfordern. Schon allein die letzte Forderung dürfte die Schwierigkeiten, die schon bei der herkömmlich bekannten Verfahrensweise auftreten, wesentlich erhöhen.According to the applicant's knowledge, the effect of the mask designed according to the invention, which excludes the heating of the shadow mask, is due to the fact that only a metallically pure heavy metal coating ensures the uniform and continuous coating of the mask required for complete reflection of the incident electrons. Theoretically, the result of the device according to the invention could also be achieved with masks which are coated with a heavy metal oxide if it were ensured that the heavy metal oxides can be distributed so closely on the mask that the heavy metal oxide grains would lie close to one another, that is to say virtually without a joint. Besides that the last requirement cannot be met, such a formation of the protective layer would require a grain size of the heavy metal oxide particles of less than 0.5 μm. The very last requirement alone should significantly increase the difficulties that already arise with the conventionally known procedure.
Wird die Maske nach Anspruch 1 ausgebildet, hat dies den weiteren Vorteil, daß dadurch auch das thermische Verhalten der Maske verbessert wird. Dies deshalb, weil die metallische Schwermetallschicht gegenüber der aus Schwermetalloxid gebildeten Schutzschicht wesentlich dunkler ist und deshalb auch die Wärme besser abstrahlt.If the mask is designed according to claim 1, this has the further advantage that it also improves the thermal behavior of the mask. This is because the metallic heavy metal layer is significantly darker than the protective layer formed from heavy metal oxide and therefore also radiates the heat better.
Die zweitbenannte Aufgabe wird gemäß Anspruch 4 dadurch gelöst, daß die Beschichtung der Schattenmaske elektro-chemisch erfolgt. Allein diese Verfahrensführung erlaubt bei kostengünstiger Ausführung eine durchgängig gleichmäßige Schwermetallschutzschicht in hohen Stückzahlen. Der Kostenvergleich wird dazu vor allem zum Aufdampfen von Schwermetallschichten gezogen.The second object is achieved according to claim 4 in that the shadow mask is coated electrochemically. This procedure alone allows a consistently uniform heavy metal protective layer in large quantities with an inexpensive design. The cost comparison is primarily drawn for the vapor deposition of heavy metal layers.
Vorteilhafte Ausbildung der Erfindung sind in den Ansprüchen 2 und 3 für die Vorrichtung und in Anspruch 5 für das Verfahren niedergelegt.Advantageous embodiments of the invention are set out in claims 2 and 3 for the device and in claim 5 for the method.
Sehr vorteilhaft ist es die gemäß Anspruch 2 als Schwermetall Wismut zu verwenden, da es sich bei diesem Schwermetall um das einzige Schwermetall handelt, welches ungiftig ist und daher keine besondere Behandlung bzw. Verfahrensführung benötigt.It is very advantageous to use the bismuth as heavy metal according to claim 2, since this heavy metal is the only heavy metal which is non-toxic and therefore does not require any special treatment or process control.
Wird gemäß Anspruch 3 die metallische Schutzschicht mit einer Alkalisilikatschicht beispielsweise einer Natriumsilikatschicht überzogen, hat dies den Vorteil, daß das metallische Schwermetall bei nachfolgenden Arbeitsgängen, welche die Maske über die Schmelztemperatur des Schwermetalls erwärmen, nicht abtropft. Mit anderen Worten, die Alkalisilikatschicht bewirkt, daß die Haftung des Schwermetalls auf der Maskenoberfläche bei Temperatureinwirkung auf die Maske verbessert wird.According to claim 3, the metallic protective layer with an alkali silicate layer, for example one Coated with a sodium silicate layer, this has the advantage that the metallic heavy metal does not drip in subsequent operations which heat the mask above the melting temperature of the heavy metal. In other words, the alkali silicate layer has the effect that the adhesion of the heavy metal to the mask surface is improved when the mask is exposed to temperature.
Wird - wie in Anspruch 5 offenbart - das metallische Schwermetall stromlos auf der Maskenoberfläche abgeschieden, hat dies gegenüber dem elektrolytischen Abscheiden den Vorteil, daß im Vergleich zwischen Maskenrand und Maskenmitte keine Unterschiede in der Dicke der Schwermetallschicht zu verzeichnen sind. Diese Unterschiede in der Schichtdicke beim elektrolytischen Abscheiden sind nach Erkenntnissen der Anmelderin darauf zurückzuführen, daß am Maskenrand gegenüber der Maskenmitte eine Feldlinienkonzentration auftritt, welche ihrerseits die Ursache für eine stärkere Metallabscheidung in den Randbezirken der Maske verantwortlich ist. Neben der unterschiedlichen Dicke der Schwermetallschicht zwischen dem Rand der Maske und der Maskenmitte werden am Rand auch die Maskenlöcher durch die erhöhte Schwermetallabscheidung verkleinert.If - as disclosed in claim 5 - the metallic heavy metal is electrolessly deposited on the mask surface, this has the advantage over electrolytic deposition that there are no differences in the thickness of the heavy metal layer in comparison between the mask edge and the center of the mask. According to the applicant's knowledge, these differences in the layer thickness during electrolytic deposition can be attributed to the fact that a field line concentration occurs at the edge of the mask opposite the center of the mask, which in turn is responsible for a stronger metal deposition in the peripheral regions of the mask. In addition to the different thickness of the heavy metal layer between the edge of the mask and the center of the mask, the mask holes on the edge are also reduced by the increased heavy metal deposition.
Zur Ausbildung einer mit einer metallischen Schwermetallschicht versehenen Schattenmaske wird zunächst in einem Bad Schwermetalloxid in einer geeigneten Säure gelöst. Diese Säure kann beispielsweise für Wismutoxid Salpetersäure sein.To form a shadow mask provided with a metallic heavy metal layer, heavy metal oxide is first dissolved in a suitable acid in a bath. This acid can be nitric acid for bismuth oxide, for example.
Sodann wird die Schattenmaske in das zuvor angesetzte Bad getaucht. Hierbei sind zwei Dinge besonders zu beachten: Das stromlose Abscheiden erfolgt nur dann, wenn das Metall, aus welchem die Schattenmaske gebildet ist, unedler ist als das Metall, welches den Schutzüberzug bildet. Ob ein Metall edler ist als ein anderes Metall beurteilt sich aus dem Vergleich der Elektronegativität der zur Beurteilung anstehenden Metalle. Allgemein kann gesagt werden, daß mit zunehmender Elektronegativität das Metall immer unedler wird. Besteht im vorliegenden Ausführungsbeispiel die Schattenmaske aus Eisen und soll diese Maske mit einem Wismutüberzug versehen werden, besteht zwischen Eisen und Wismut ein ausreichend großer Unterschied in der Elektronegativität, so daß problemlos eine stromlose Abscheidung von Wismut auf der Schattenmaske erfolgen kann.Then the shadow mask is placed in the previously installed bathroom submerged. Two things are particularly important here: Electroless plating takes place only when the metal from which the shadow mask is made is less noble than the metal that forms the protective coating. Whether a metal is more noble than another metal is assessed by comparing the electronegativity of the metals to be assessed. In general it can be said that with increasing electronegativity the metal becomes less noble. If, in the present exemplary embodiment, the shadow mask is made of iron and if this mask is to be provided with a bismuth coating, there is a sufficiently large difference in electronegativity between iron and bismuth so that bismuth can be deposited without current on the shadow mask.
Der weitere Punkt, der beim stromlosen Abscheiden von Schwermetall auf der Schattenmaske beachtet werden muß, ist das Eintauchen der Maske in das Bad bzw. das Entfernen der Maske aus dem Bad. Da die Maske ein sehr labiles Gebilde ist, welches sehr leicht zu Verformungen neigt, ist es notwendig die Maske so langsam in das Bad einzusetzen bzw. aus dem Bad zu entfernen, daß durch diesen Vorgang mechanische Beschädigungen der Maske etwa in der Form von Beulen ausgeschlossen werden.The further point that must be observed when current-free deposition of heavy metal on the shadow mask is the immersion of the mask in the bath or the removal of the mask from the bath. Since the mask is a very unstable structure, which tends to deform very easily, it is necessary to insert the mask into the bath or remove it from the bath so slowly that mechanical damage to the mask, for example in the form of bumps, is excluded by this process will.
Hat die Maske im Bad ausreichend lange reagiert, indem Eisen aus der Maske in Lösung gegangen ist und sich beispielsweise Wismut aus der Lösung auf der Maskenoberfläche abgeschieden hat, wird die Maske aus dem Bad entfernt.If the mask has reacted in the bath for a sufficiently long time, because iron has dissolved out of the mask and, for example, bismuth has deposited from the solution on the surface of the mask, the mask is removed from the bath.
Zur Haftungsverbesserung des Schwermetalls auf der Maskenoberfläche kann die beschichtete Maske nach einem Waschvorgang in ein weiteres Bad eingesetzt werden, welches eine Alkalisilikatlösung beispielsweise in der Form einer Natriumsilikatlösung enthält. Wird sodann die Maske aus dem letzt beschriebenen Bad entfernt und die auf ihrer Oberfläche haftende Natriumsilikatlösung getrocknet, wird die Temperaturbeständigkeit der Schwermetallschutzschicht erhöht. Insbesondere wird dadurch ein Abtropfen von metallischem Schwermetall verhindert, wenn bei nachfolgenden Bearbeitungsschritten die Maske über den Schmelzpunkt des Schwermetalls hinaus erwärmt wird.
Ergänzend wird darauf hingewiesen, daß, wenn die Maske in ein Alkalisilikatbad eingetaucht wird, die Verfahrensführung so gestaltet sein muß, daß auch hier eine Beschädigung der Maske vermieden wird.To improve the adhesion of the heavy metal on the mask surface, the coated mask can be applied after a Washing process can be used in another bath containing an alkali silicate solution, for example in the form of a sodium silicate solution. If the mask is then removed from the bath described last and the sodium silicate solution adhering to its surface is dried, the temperature resistance of the heavy metal protective layer is increased. In particular, metallic heavy metal is prevented from dripping if the mask is heated beyond the melting point of the heavy metal in subsequent processing steps.
In addition, it is pointed out that if the mask is immersed in an alkali silicate bath, the procedure must be such that damage to the mask is also avoided here.
Claims (5)
dadurch gekennzeichnet,
daß die Schattenmaske zumindest auf der Seite, die dem Elektronenstrahlerzeugersystem zugewandt ist, durchgängig mit einem gleichmäßig dicken Schutzüberzug versehen ist, der aus metallisch reinem Schwermetall gebildet ist.Shadow mask for picture tubes,
characterized,
that the shadow mask, at least on the side facing the electron gun system, is continuously provided with a uniformly thick protective coating which is formed from pure metallic heavy metal.
dadurch gekennzeichnet,
daß das Schwermetall, welches die Schattenmaske als Schutzüberzug überdeckt, Wismut ist.Shadow mask according to claim 1,
characterized,
that the heavy metal that covers the shadow mask as a protective coating is bismuth.
dadurch gekennzeichnet,
daß der schwermetallische Schutzüberzug mit einer Alkalisilikatschicht überzogen ist.Shadow mask according to claim 1 or 2,
characterized,
that the heavy metal protective coating is coated with an alkali silicate layer.
dadurch gekennzeichnet,
daß die Beschichtung der Schattenmaske elektro-chemisch erfolgt.Process for coating shadow masks with heavy metal,
characterized,
that the shadow mask is coated electrochemically.
dadurch gekennzeichnet,
daß das metallische Schwermetall auf der Maskenoberfläche stromlos abgeschieden wird, indem die Schattenmaske, welche aus einem Metall gebildet ist, das unedler als das Schwermetall für die Schutzschicht ist, in ein Bad abgesenkt wird, in welchem zuvor das Schwermetalloxid in Säure gelöst wurde.Method according to claim 4,
characterized,
that the metallic heavy metal is electrolessly deposited on the mask surface by lowering the shadow mask, which is formed from a metal that is less noble than the heavy metal for the protective layer, into a bath in which the heavy metal oxide has previously been dissolved in acid.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19914118734 DE4118734A1 (en) | 1991-06-07 | 1991-06-07 | SHADOW MASK FOR PIPES |
| DE4118734 | 1991-06-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0522273A1 true EP0522273A1 (en) | 1993-01-13 |
Family
ID=6433406
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP92108830A Withdrawn EP0522273A1 (en) | 1991-06-07 | 1992-05-26 | Shadow mask for picture tubes |
Country Status (2)
| Country | Link |
|---|---|
| EP (1) | EP0522273A1 (en) |
| DE (1) | DE4118734A1 (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2072223A (en) * | 1980-03-21 | 1981-09-30 | Philips Nv | Method of blackening steel components |
| NL8004076A (en) * | 1980-07-16 | 1982-02-16 | Philips Nv | Colour TV tube with luminescent zones on screen - has shadow mask electrode coated with layer of lead deposited by galvanic process |
| US4339687A (en) * | 1980-05-29 | 1982-07-13 | General Electric Company | Shadow mask having a layer of high atomic number material on gun side |
| US4442376A (en) * | 1980-07-16 | 1984-04-10 | U.S. Philips Corporation | Color display tube having heavy metal coating on color selection electrode |
| EP0366523A1 (en) * | 1988-10-25 | 1990-05-02 | THOMSON TUBES & DISPLAYS SA | Imaging shadow mask tube, mainly for colour television |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3562518A (en) * | 1967-11-21 | 1971-02-09 | Nat Video Corp | Color kinescope with improved x-ray protection |
| JPS493458U (en) * | 1972-04-12 | 1974-01-12 | ||
| JPS5576553A (en) * | 1978-12-05 | 1980-06-09 | Mitsubishi Electric Corp | Color braun tube |
| JPS61273835A (en) * | 1985-05-29 | 1986-12-04 | Mitsubishi Electric Corp | Manufacture of shadowmask |
-
1991
- 1991-06-07 DE DE19914118734 patent/DE4118734A1/en not_active Withdrawn
-
1992
- 1992-05-26 EP EP92108830A patent/EP0522273A1/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2072223A (en) * | 1980-03-21 | 1981-09-30 | Philips Nv | Method of blackening steel components |
| US4339687A (en) * | 1980-05-29 | 1982-07-13 | General Electric Company | Shadow mask having a layer of high atomic number material on gun side |
| NL8004076A (en) * | 1980-07-16 | 1982-02-16 | Philips Nv | Colour TV tube with luminescent zones on screen - has shadow mask electrode coated with layer of lead deposited by galvanic process |
| US4442376A (en) * | 1980-07-16 | 1984-04-10 | U.S. Philips Corporation | Color display tube having heavy metal coating on color selection electrode |
| EP0366523A1 (en) * | 1988-10-25 | 1990-05-02 | THOMSON TUBES & DISPLAYS SA | Imaging shadow mask tube, mainly for colour television |
Also Published As
| Publication number | Publication date |
|---|---|
| DE4118734A1 (en) | 1992-12-10 |
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