DE2629140A1 - TELEVISION TUBE PISTON AND METHOD OF MANUFACTURING THEREOF - Google Patents

Description

"TV tube flask and method of doing it

Manufacture "

The pistons for television tubes are generally manufactured in that the curved face plate and the cone with Neck produced separately and then the two parts are fused to form the piston. The two parts can blow through the glass mass or pressing in a mold. The pressing technique is preferred for economic reasons.

Two problems arise in the manufacture of television tubes. The first is the picture quality, which also depends on the quality of the domed faceplate depends, and the second problem is the connection of the faceplate with the cone to the designated Mating surfaces.

The front panels for television tubes were previously exclusively mechanically ground, which is a complex process and

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requires the utmost care. From DT-OS 1 512 562 are sunken and rimless mirror glass panes as front panes known for television picture tubes. When it comes to a mirror glass it is a mechanically ground or mechanically polished glass on both sides.

The mating surfaces of the front disk and cone have so far essentially been machined and ground, what is also a very complex process for a good fit. Attempts have already been made to find the edge areas To chemically polish mechanically ground front panels, however, this is an additional process step required besides polishing the faceplate.

The object of the invention is now a television tube piston which improves the picture quality of the picture tubes produced therewith results in simultaneous processing by optimizing the reflection values of the curved faceplate on both sides the mating surface of the faceplate for connection to the mating surface of the cone.

This object is achieved according to the invention in that the curved front panel on the inside and outside in the screen

^to possibly

area and / the edge area around the mating surface are chemically polished. This polishing is done in a known manner Way with a hydrofluoric acid containing sulfuric acid, whereupon it was optimized with regard to the screen area Front plate is processed further with an already perfectly machined mating surface against the cone to the piston.

Through the measure according to the invention of chemically polishing both interfaces between glass and air, showed Surprisingly, that much brighter, so more luminous Screens can be obtained.

As mentioned, one has already mechanically leveled both sides

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Ground front panes, i.e. made of mirror glass, were used. The aim was to have an absolutely evenly ground interface between air and glass, whereby these two interfaces had to be optimally plane-parallel. It is easy to understand that these are optical Requirements for the curved windshield are complicated Work processes and cause high costs. In contrast, the chemically polished according to the invention Boundaries do not represent absolutely flat surfaces, but rather show a facet-like appearance in microscopic dimensions Surface. Because of these microscopic unevenness of the chemically polished surfaces according to the invention are at the windshields according to the invention, these are also not exactly plane-parallel at every point.

This fact that one with the invention chemically ■ polished surfaces result in a significantly improved visibility of the screen images in television tubes made from them, is very surprising to the professional world and is contrary to their view, which has been set out above. A Another advantage of the invention is that simultaneously with the chemical treatment of the surfaces in the The mating surface is chemically polished and in this way a separate process step for the processing of the screen area The mating surface of the front window is dispensable.

The double-sided polishing of the front plate for flasks and television tubes According to the invention, one of the known chemical polishing processes can be used. As particularly suitable the process according to DT-PS 1 185 780 has proven itself, with the in'der pressing device made of the usual special glass manufactured front panels are first dipped several times in a polishing bath made of hydrofluoric acid and After each immersion, the salt deposit is removed in a washing bath made of dehydrating sulfuric acid. After attainment the desired polish is rinsed off with water and dried, and the plate is then fused with the cone.

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In principle, “this polishing process can be carried out in the usual systems for polishing glass objects. A basket with a base in For * ¹ ! a bar grating and side walls provided with vertical slots. In this basket there are one or more compartment inserts, consisting of a number of comb strips arranged parallel to each other and at a distance from each other with retaining strips inserted perpendicular to them (DT-PS 1 596 991) β The items to be polished, i.e. the front panels, are placed in the compartments of the basket and then polished on both sides in a known manner.

As already mentioned above, such acid polishing baths are known for the most varied types of glass, which can also be used here. In general carried out with sulfuric acid concentrations of 40-66 $, The hydrofluoric acid content is between 1 and $ 12, and the working temperature "doors in general between 20 and 6O ⁰ O. is polished with an alternating treatment and Schwefelsäurewaschbad, one used for a 60 to 76 fo ± ge sulfuric acid solution with a temperature between about 60 and 8O ⁰ C.

The invention is illustrated by the following examples. example 1

It was used a polishing acid containing 5 i ° hydrofluoric acid and 50 $> sulfuric acid at 20 ° c. The front plates to be polished were immersed in the polishing acid for 10 times 40 s and in between 8 s in a 67% sulfuric acid solution at 68 ° C. _to remove the salt deposit formed during the polishing reaction. After this alternate treatment, the required degree of polishing was achieved. The front panel could be rinsed with water and dried. The television tubes made from these faceplates showed improved screen visibility, "-.-- ..

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Example 2

It was used a polishing acid, containing 6% hydrofluoric acid and 45 1 of sulfuric acid at 4O ° ⁰ O. The front panels to be polished were immersed in the polishing acid once for 5 s, then once for 30 s and then 6 times for 60 s and in between each 5 to 10 s in the sulfuric acid wash bath in the form of a 70% sulfuric acid solution at a temperature of 66 ° C. After the desired degree of polishing was achieved, the front panels were rinsed with water and dried.

The television tubes produced with it showed a perfect screen image, the polished mating surfaces could be easily connect with the cone "

Example 3

In this case, a 58 $ strength by weight sulfuric acid solution containing 8 applied io hydrofluoric acid at 50 ⁰ G for polishing. The immersion times in the polishing bath were 1 times 5 s, 1 time 30 s and finally 5 to 8 times 60 s, in between again 5 to 10 s in a sulfuric acid wash bath in the sense of the above examples.

Here, too, you got flawless front panels that can be easily connected to the cone.

Example 4 ¹

The polishing acid containing 62% sulfuric acid and 12 $ hydrofluoric acid and had a temperature of 55 ⁰ G. It was 1 times 5 s, 1 times 20 s and then 1 χ 30 s and finally 7 times 60 s above in the polishing and in between as in Examples immersed in the sulfuric acid wash bath.

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The front panels were perfectly polished and the connection of the mating surfaces with the cone was satisfactory,

Containing one used for a single dipping operation acid a polishing, 64 i ° sulfuric acid and 3 $ iTußsäure at 6O ⁰ C. The immersion time was 7 min. Thereafter, the desired degree of polish was obtained "The front panels were rinsed with water, dried and processed for the piston . The results were perfect.

Claims

609885/0743

Claims (3)

Sponsorship claims G) ¹ KJ television tube flask, characterized in that the inside and outside of the front plate in the screen area are chemically polished. 2. TV tube flask according to claim 1, characterized in that that the mating surface, via which the connection with the cone takes place, by chemical means is polished. 3. A method for producing the television tube piston according to claim 1, characterized in that the front panel is polished on both sides and, if necessary, in the edge area with a hydrofluoric acid containing sulfuric acid, the salt deposit that forms during the polishing reaction is removed, the front panel washes acid-free and with it in a known manner a glass solder connects the mating surface of the front plate with the correspondingly treated mating surface of the cone. 8183 609 88 5/0743