DE2021505A1 - Glass for television viewing electron beam tubes - Google Patents

Description

üVpi.-lnr. HOP.ST A ¹ JER ^{Ϊ <ι / Β7} ·

A ^ -Idcr: MV? R; _.... .:.,? £ κΡΑΒΗΙΕΚΕΐί ·
Aide: PHH "- 4059

dated: April 30, 1970

Glass for television viewing cathode ray tubes.

You invention relates aioh to glass for a piston Television viewing electron beam tubes, in particular glass for windows such a tube.

Fernsehbildwiedergabeelektronenetrahlröhren black and white, such a special glass are applied to glass for pistons of Farhfernsehbildwiedergabeelektronenstrahlröhren in comparison to glass for pistons of particularly high demands, Aue is British patent specification 1,123,857 is known whose composition in weight. I »within the following limits liegtt

SiO ₂ 62-66 MgO 0-5

Li ₂ O O- 1 PbO 0-2

H * ₂ Ö 7 - 8.5 Al ₂ O ₃ 1-4

009847 / 11S ₈

202 1 505 _F 0 4059 , 7 Sb ₂ O 3 0 , 5 - O , 5 , 05-0

K ₂ O 6.5-9 Ab ₂ O

CaO 2 -4 »5 CeO ₂

BaO 11-14.

The particular strict requirements that Compared to Glass for flasks from black and white display tubes to glass for flasks of color reproduction fees are attached with differences the manufacture and use of this drilling. In the first place the glass parts for the bulbs of color television tubes not, as with the pistons of black-and-white display tubes, are fused together, but must be connected to one another with the help of enamel. This is necessary because in these Drilling a shadow mask is provided showing the way the three needed Electron beams determined. It is also on the inside of the screen an extremely fine grid-like pattern of three different phosphors corresponding to the openings of the perforated mask. The requirements with regard to the maximum permissible deformation of the glass are therefore much stricter in this case than in the case of glass for pistons of black-and-white reproducers. In addition, there is the temperature on which the tube must be heated to about 20 * higher during evacuation and the The duration of the heating can be longer than with black-and-white display tubes got to·

The glasses within the above-mentioned range have proven themselves technologically with regard to the softening temperature, the quality and the thermal expansion coefficient. at the acceleration voltages used until recently on the electron beam generation systems is the absorption of these glasses for the X-rays generated during operation as a result of the electron impact

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large enough on the glass and the shadow mask. This is even true too, if the tube is in a direct line version, thus without protective Cover plate, is built into a housing.

• Up to now it was necessary that with a maximum thickness of the Screen glass of 11 mm, an accelerating voltage of 27.5 kV and an anode current of 3 χ ΙΟΟ ^ ώΆ in a television display tube the The intensity of the transmitted X-rays is a maximum of 0.5 milli-x-rays per hour (mr / h).

However, there is a desire to increase the safety margin to keep increasing the X-rays emitted by television display tubes. There is now a need for a type of glass in which an acceleration voltage of up to 40 kV at most 0.5 mr / h will. The absorption of the glasses described above is then no longer sufficiently high that they do not meet the increased security requirements. For technological reasons, the thickness of the screen can increase cannot be increased much more than 11 mm. In order to use a glass lying within the above-mentioned composition range To obtain a sufficiently high absorption, the thickness of the screen would have to be at least 2.5 mm greater.

For satisfactory processing of the glass and for fretting windows made of this glass, it is necessary that the temperature dependence of the viscosity is not too great. In practice, this means that the temperature difference between the softening point, ie »the temperature at which the viscosity of the glass is 10 poises, and the upper cooling point (annealing point), ie the temperature at which the viscosity of the Glass is 10 ¹⁵ ' ⁴ poieee, must be at least 190 ° C.

0 098 47/116 ₈

-4- a U Z I 0 U O PHN. 4059

In connection with the usual manufacturing technique and the particularly strict requirements for the maximum permissible deformation If the glass parts are placed in the manufacture of the tube, it is necessary that a glass for a color tube has an upper cooling point of not less than 485 * C.

Finally, it is important that a glass for a color television display tube has approximately the same coefficient of expansion as the known glasses (about 100 χ 10 ""'between 30 and 300 ° C), so that this glass corresponds to the existing glass and metal parts to be melted adapts.

The aim of the invention is to make glasses for the pistons of television viewing tubes, in particular of color television display tubes, to meet all the requirements mentioned, including the requirement of a Maximum of transmitted X-rays of 0.5 mr / h one display tube containing such glass with a screen about 11 mm thick, an acceleration voltage of up to 40 kV at an anode current of 300 / έΑ.

In the USA patent specification 2,527,693, glass for cathode ray tubes is used with a coefficient of expansion between 87 and 93 χ 10 ~ 'with a softening temperature below 720 ^a C. and a difference between the softening temperature (^ J? - 10' * ³ poises) and the lower Cooling point (^ - 10 ^ * poises) described by more than 215 ^# C. These glasses have a composition in terms of weight within the following limits

SiO ₂ 0 53 - 75 Al ₂ O ₃ 0 3 - 15th K ₂ O 0 ,1 - 13th Ha ₂ O ♦ 1 - 17th Li ₂ O , 5 - 2

0Q9847 / 116 ₈

total alkali oxide between 16 - ~ [ßao and I9 - 1 I construction]

-5- 2021 5ν, j ^ _{4Ο59 (}

BaO 5 - 28th

F 0.5-2.5.

It turned out that within this compositional range some glasses were in which the above-mentioned dose of transmitted X-rays at an accelerating voltage of 55 fcV remains below 0.5 mr / h, namely the glasses with a high BaO salary of $ 17 and higher. This glass is not suitable for Use in color rendering because of the expansion coefficient

—7 "■ ■■■■■ '

about 10 χ 10 ', is too low. The presence of fluorine in general lowers the softening temperature of glasses is also considered to be less desirable. Namely, it attacks the ones used when eating Tools strongly.

Another major disadvantage, however, is that this known glass shows disturbing devitrification phenomena »whereby it is not suitable for melting in large tanks and for the automatic production of pressed piston parts for color television playback tubes. Glasses with a high BaO content generally have such a tendency to devitrify.

The invention creates a particularly satisfactory solution, in which there is no problem with respect to the tendency to devitrify.

The glasses according to the invention are characterized in that their composition in wt.% Is within the following limits * SiO ₂ 54-69

Na ₂ O 4 - 8Λ

i pfa _p OJ + [K-Oj total 14-20 K ₂ O 6-15 J ^{l J}

-6-. 202150 ^.

MgO 0-1.5

CaO 0-4

BaO 0 -18 Λ flBaoi + 2 fsrO] + 4 ^ ₀ θΓ |> 16

/ JLJ L J I 2 3J

SrO 1 -16 j L ^Bft0 ] ⁺ iifsroL <28.5

GeO _{0 0.05-0.5}

o- ₅ y

O-O, 3. i

Sb O

As ₂ O ^ η χ ι - ^ ^ 5

Venn the absorption for X-rays as a puncture of the Accelerating voltage is represented, there is a decrease in the Absorption for SrO, BaO and 3b_0 in the voltage range of 25 - 37.3 kV. At the latter voltage, a discontinuity occurs for BaO «The absorption is increased by a factor of 5 in steps and then falls slowly decreases as the tension increases. This means that if the X-rays transmitted over 37.3 - 40 kV below the standard value of 0.5 mr / h should be kept, the presence of BaO in the glass is appropriate is, so that such a glass is particularly cheap. The acceleration voltage just below the unsteadiness at 37 »3 kV is critical for absorption at lower voltage. When the permeability is still sufficiently low just below 37.3 kV, this is it even with even lower acceleration voltages of the Case. At higher voltages, a relatively low BaO addition, the permeability for X-rays slightly below the admissible limit value are kept

A more preferable one within the above-mentioned compositional range lying area within which glasses are located, in which the transmitted X-rays are at least up to 37 »3 kV below 0.5 mr / h remains, is (in wt. ^ The following

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SiO ₂ 54 - 65 Na ₂ O 4 - 8 ^) κ ₂ ο ■ 6 - 13 y Al ₂ O ₅ 1 - / 7 MgO 0 - 1.5 CaO O- 4th BaO 2.5 - ¹⁶ 1 SrO 5 - -.16. I. CeO ₂ 0.05- 0.3 Sb ₂ O ₃ o - 3 As ₂ O 0 - 0.3

a total of 14 - 20

[Bad] + 2TsrOl + 4 ["Sb ₂ O ₃ I ^ 25 + 1 ^ [srOj <28.5

^A8 2 ° 3 ^{+ Sb} 2 °

A preferred range lying within this range, within which glasses lie in which the transmitted dose of X-rays up to 40 kV remains below 0.5 rare / h and which also have the advantage that this is achieved with a minimum amount of heavy alkaline earth metals, whereby the specific weight is relatively low, the following is in weight ic :

SiO ₂ 61 - 65 Na ₂ O 6 ■ -. 12 y κ ₂ ο 6 - 5 Al ₂ O ₃ 1 - 1f5 HgO 0 - 4th CaO 0 - ¹⁰ I.
13 y BaO 4 - 0.3 SrO. 8th - 3 CeO ₂ 0.05- 0.3 Sb ₂ O ₃ 0 - AB ₂ O ₃ 0 -

J [Na ₂ O] + [K ₂ O] total 14 -

26 <[Bao] + 2 ["SrOJ

. [Sb ₂ O ₃ ] _> 0.3

ÜO98A7 / 116 ₈

2021 5

For example, below are some glasses after Invention indicated with the essential physical quantities. she were made in the usual manner in glass technology by melting a Mixture of sand, potassium feldspar, sodium carbonate, dolomite, strontium carbonate and cerium oxide and, if necessary, barium carbonate potassium carbonate, Get magnesium carbonate and / or calcium carbonate. Arsenic trioxide and antimony trioxide were added as fining agents.

009847/1168

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■ Τ CTN M ■ WN CM ιη VO in 1 j τ— CTN VO CO τ— T- Ε KN aw co O O in C— κ ■ r- - - ■ CM VO
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VO CO VO T- VO r- I. T- O VO CM VO in T " KN T— O O CM* KN t— T- L— VO O O KN CM t— T— I. I. ·% ' O vO CM , - • ^ " CTn ON VO 4Ί ■■ • x KN flh. ¹ ^ " VO in T- KN T— O O τ— CM CVI CM T " CO CfN - ^ J- ON co ON O O m ■> * · " O T- in O VO CM in C- ^ _ in Q KN T- CM _O O O co T— c— CTN ON co ■ 'a in On O m , _ in KN I. I. in O VO CM C- VO d * VO τ- CM* O O 4 »
JU O O J » O •H * O > ^ - " Φ ■ approx CM 4 » · < O KN • •H ■ ri O O O O Ο KN O t9 to CM O CM tip (β α) O O CM β) a CM r-i SR O A. U CM O) pi CQ JCk O ω CO j! O) α> CQ Ö Φ α)
frt W. C * 3

PHN. 4059

009847/1168

202 IbUb

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τ- • Η
C- Wt
00 CM ιη ιη O ο " C- Ο ON CM νο τ— U.N. VO OO
T- ιη VO CM CM CM ιη VO CM O VO ω C- ιη O ιη νθ O O. O ON CM ιη τ- T- ιη VO ΟΝ I. ιη , _ C-- ON VO CD ιη I. I. f— VO CM τ- O C-
0k CM C- CM I. ιη CM O O C- Ο ON CM VO Τ U.N. VO νθ O ο O I. O ιη Ο VO CM CM ON , ^ τ-
C- Xt C- C- CM CM νο O O O co O ^^ CM VO τ- U.N. C- > g Φ te ιη ιη ιη ιη O I. O ON CO VO CM KN 00 O C- CM σο " CM WN Xt O O O CO O ON CM VO Τ xt U.N. VO 3 N Φ U.N. m T- Xt C- O I. O O Ο VO CM CO KN C- β
φ T- C- C- CM KN ON σ \ O O co T- O CM B. VO Xt U.N. S. approx OO CM τ- χΐ- xt ιη O I. KN νθ νθ CM xt Κ \ Ο C- N W * χ? CM I. O C- O O co T- CM CM νθ τ- τ- U.N. C- CM KN m VO Xt ιη I. ιη C- νθ CM O O C- CM C- CM I. O* O C- O ON CM* VO U.N. νθ ■ 4 » Λ ο O O 0 ϋ • Η * 4 » egg KN « • . CM O O CM O 4 » N O CM O te O Ο ο CM O * * Φ • Η 0} CM «Β «Β U pi CO te O CO CO ο CO

009847/1168

- • μ-, / Uz IbUb _ΡΗΝί

The low relaxation stone temperature (L.O.T., strain point)

ΛΑ (\ -

iet the temperature at which the viscosity is 10 * V poises; the high de-tensioning temperature (H.0.T .; annealing point) is the temperature at which the viscosity is 10 * ' ⁴ poiaes * and the softening point (VT, softening point) is the temperature at which the viscosity is TO ⁷ ' ⁶ Poises is.

009847/1168

Claims (1)

PATENT CLAIMS * · Glass for the flasks of television display electron beam tubes, especially for the window of such a tube, which contains SiO ₂ , alkali oxide, barium oxide, calcium oxide, aluminum oxide, cerium oxide and arsenic and / or antimony oxide, characterized in that the composition in Geν «56 within the The following limits are SiO ₂ 54-69 ^Na 2 ° ⁴ " ^e *) r 1 Γ Τ / IKa ₉ Ol ₊ j K ₀ O total I4 - 20 K-O 6-153 Al ₂ O ₃ 1-7 MgO 0-1.5 CaO 0-4 BaO 0 - 18 \ [BaC-] + 2 [sro] + 4 [sbgO]> 16 SrO 1 - 16 j | Bao 1 + 1 ^ [Srol <. 28.5 CeO _{2 0.05-0.3} Sb ₂ O ₃ 0-3 V _{o + o} As ₀ O- 0 - 0.3.) * - ^ L 2 3J 2. Glass according to claim 1, characterized in that it is in . Ia located within the following weight Zusaaaensetzungsbereicb.es: 60-65 (l? ^e 2 °] ⁺ t ^K 2 °] Na 0 4-8 [ | Na ₉ 0 | + IK ₀ O j total of 14-17 K ₂ O 6-13 Al ₂ O ₃ 1-7 MgO 0-1.5 CaO 0-4 BaO 2.5 - 16 ") [BaO] + 2 [sro] + 4 SrO 5 - 16 J [BaO] * * * 1 ^ i [srO] <. 28.5 009847/1168 CeO ₂ 3 · Glass according to claim 1, characterized in that it is in% by weight within the following composition range ι ■ ■. 61-65 6 - 8 Y V total 14 - 17 6 - 12 years Al ₂ O ₃ 1 - 5 MgO 0 - 1.5 CaO 0 - 4th BaO 4 - SrO 8th - 13th CeO ₂ 0.05 ■ -. 0.3 Sb ₂ O ₃ Q- 3 As ₂ O ₃ 0 - 0.3 _r _ _ _η 26 <[BaOJ + [2SrOJ in total 4. Glass according to claim 3 characterized in "that it hat in wt. Is the following Zusamaeasetzung SiO ₂ 64.0 BaO 6.5 Na ₂ O 7.0 SrO 10.0 K ₂ O 7.7 Sb ₂ O ₃ 0.6 Al ₂ O ₃ 2.0 CeO ₂ 0.2 CaO 2.0. 5 »Cathode ray tube with a glass bulb according to one of the Claims 1 to 4 consists. 6 · Window for a cathode ray tube made of glass after a » of claims 1 to 4 · 0 098 4 7 / 1Ί68