US3339777A

US3339777A - Cathode ray tubes

Info

Publication number: US3339777A
Application number: US263152A
Authority: US
Inventors: Gunter J Barz; Kuffer Johannes; Haider Hugo; Ritter Johannes
Original assignee: Telefunken Patentverwertungs GmbH
Current assignee: Telefunken Patentverwertungs GmbH
Priority date: 1962-03-08
Filing date: 1963-03-06
Publication date: 1967-09-05
Anticipated expiration: 1984-09-05
Also published as: DE1439586B2; DE1439589A1; GB1035243A; DE1439586A1

Description

Sept. 5, 1967 G. J. BARZ ETAL 3339;777

CATHODE RAY TUBES Filed March 6, 1963 Ill!!!)lllllllllllili I INVENTORS GUNTER J. B|ARZ JOHANNES .v KUFFER HUGO HAIDER HELMUT s. THIELE JOHANNES 0. FR. RITTER BY wgg g ATTORNEYS United States Patent 3,339,777 CATHODE RAY TUBES Giinter J. Barz, Johannes Kiiifer, and Hugo Haider, Ulm (Danube), Helmut Thiele, Senden filler), and Johannes Ritter, Herrlingen, Germany, assignors to Telefunken Patentverwertungs-Gm.b.H., Ulm (Danube), Germany Filed Mar. 6, 1963, Ser. No. 263,152 Claims priority, application Germany, Mar. 8, 1962, T 21,718; Mar. 21, 1962, T 21,798 25 Claims. (Cl. 220-21) The present invention relates to cathode ray tubes.

More particularly, the present invention relates to an implosion protective device for cathode ray tubes, such as television picture tubes, as well as to a method for manufacturing such implosion protective device. The implosion protective device comprises a rigid frame which encompasses the tube in the region of its largest diameter and is spaced therefrom, the interspace between the frame and the wall of the tube being occupied by a filler mass which, when cold, is itself rigid.

It is known to equip a tube with a rigid frame which surrounds the tube in the region of its largest diameter, which frame firmly grips the tube thereby to lessen the consequences of an implosion which may result from damage to the tube. It is also known to use the frame for mounting the tube within a housing. The frame is generally secured to the wall of the tube by means of a filler mass. This filler mass between the tube wall and the frame, which latter is ordinarily made of metal, is, for example, sulphur, gypsum, or cement.

The present invention provides new filler masses which have a number of advantages over the heretofore known filler masses. According to the present invention, there is provided a filler mass having the following characteristics:

(a) The material stays solid up to a temperature of at least 80 C.

(b) The material is highly liquid at temperatures of between approximately 100 C. and 180 C., and preferably at temperatures of between 135 C. and 150 C.

(c) While the material is in solid state, there is no volatilization which causes odors or corrosion.

(d) The material sets or hardens within a short period.

(e) The material does not undergo an appreciable volumetric change as it goes from liquid to solid state.

The filler mass may also be constituted by sand, preferably with binder, or by a mixture that contains at least 20% sand.

A television tube equipped with a protective device according to the instant invention is illustrated in the accompanying drawing in which the single figure is a sectional view of a thus-equipped tube.

As shown in the drawing, the cathode ray tube, which may be a television picture tube 1, is equipped with a frame 2 which surrounds the tube in the region of its maximum circumference. The frame comprises two annular pull-exerting bands or

straps

2a, 2b, which have peripheral flanges 3a, 3b, that are firmly connected to each other as, for example, by means of a channel-shaped fold. In practice, the front strap 2b is so configured as to outline the viewing screen of the cathode ray tube.

The frame is somewhat larger than the outer diameter of the tube so that even those picture tubes which are within the prescribed tolerances-a little oversized will still be readily accommodated within the frame. In order firmly to secure the frame to the picture, tube, the interspace 4 between the frame and the wall of the tube is filled with a filler mass. This filler mass can be introduced into interspace 4 by letting it flow, while in liquid state, from the conical side of the tube into the interspace. In order to stop the flow of the liquid material, the strap 2b may carry suitable sealing means such as sealing rings 5.

"ice

Under certain circumstances, it has been found desirable to provide additional sealing means 5a to close off the other end of the interspace, which sealing means are put in place after the filler mass has been poured into the interspace. In this way, the filler mass can be protected against external influences, as, for example, humidity.

The

straps

2a, 2b, may be made of any suitable material, such as metal, or the frame may be a single preformed plastic part made of a polyester glass fiber mixture. According to another feature, the sealing means consist of a cement which is fashioned, for example, into the shape of an annular bead which is placed into the front strap 2b. In this way, the tube presses against the cement bead and thus seals the space between the tube and frame at the point of engagement. Under certain circumstances, it is desirable to place further sealing means 6 between the flanges 3a and 3b so as to prevent the filler material, which is still highly liquid when it flows into the interspace 4, from seeping out of the seam of the flange. The sealing means 6 may consist, for example, of a cement, a glue,

an adhesive, or the like.

It has been found important that the filler mass itself does not cause any vapor pressure. This means that the material consisting the filler mass must be such that, in the region of the operating temperature of cathode ray tubes, which region is up to approximately C., there must be no evaporation or volatilization effect which could give rise to objectional consequences, such as the formation of odors and the generation of corrosive vapors. If, for example, the filler mass is sulphur, the same will volatilize and attack the circuit elements ordinarily used with cathode ray tubes.

It has also been found that the filler mass of the above type should not have too high a melting point. The material should be highly liquid between C. and 180 C., and preferably between the narrower range of C. to C., furthermore, the material should be such that, upon solidification, it undergoes as small a volumetric change as possible. In particular, the material should be of such a nature that it does not shrink upon solidification.

It has also been found advantageous to addcolor pigments to the filler mass, in order to prevent, for example, a picture tube which is not in use from appearing in different colors due to reflection effects. The pigments may, for example, be black color pigment.

The following are examples of filler masses according to the present invention, all of which have the abovedescribed characteristics.

EXAMPLE 1 The filler mass consistsof urea to which salicyclic acid or benzoic acid as well as wax, bitumen and kieselguhr (diatomaceous earth) are added. The salicyclic or benzoic acid serves to make the filler mass less Water soluble and to prevent the decomposition of the molten urea. The wax and kieselguhr also reduce the water solubility. The filler mass may also have added to it solid particles such as" cuttings or shavings, as, for example, mechanical wood pulp, sand, or porcelain powder, the porcelain powder, for example, additionally acting as crystallization nucleus.

As an example the following filler masses may be 3 EXAMPLE 2 bitumen polyethylene wax EXAMPLE 3 The filler mass consists of colophony with a softening agent for instance of Percent by weight (a) colophony 80-90 triphenylphosphate 10-20 (b) colophony 80-90 diphenylcresylphosphate 10-20 EXAMPLE4 The filler mass consists of chlorinated naphthaline. The amount of chlorination in the naphthaline is not critical. Any chlorinated naphthaline as it is sold by many companies can be used.

EXAMPLE 5 sugar kieselguhr EXAMPLE 6 The filler mass consists of alum to which cuttings or shavings are added. In the case of such a filler mass the additional sealing means at the edges have been found to be particularly advantageous. The filler mass may consist for instance of Percent by weight (a) alum 70-80 sand 20-30 (h) alum 70-80 porcelain powder 20-30 EXAMPLE 7 The filler mass consists of phthalic (acid) anhydride to which cuttings are added as for instance of Percent by weight (a) phthalic anhydride 70-80 sand v 20-30 (b) phthalic anhydride 70-80 porcelain powder 20-30 EXAMPLE 8 The filler mass consists of betanaphthol to which cuttings are added as for instance of Percent by weight (a) betanaphthol 70-80 sand 20-30 (h) betanaphthol 70-80 porcelain powder 20-30 EXAMPLE 9 The filler mass consists of chlorinated polyethylene to which cuttings are added as for instance of Percent by weight chlorinated polyethylene 95-99 kieselguhr 1-5 4 EXAMPLE 10 The filler mass consists of paraflin with wax additives and cuttings as for instance of Percent by weight (a) parafiin -99 hard wax l-10 (b) parafiin 90-99 hard wax 105 l-10 triphenylphosphate 1-5 Each of the above-mentioned filler masses has the characteristic that it becomes highly liquid (highly liquid being intended to refer to a liquid having a viscosity of 20-100 centipoise, preferably 30-80 centipoise, at a temperature of between 100 C. and 180 C., and generally between about C. and C., and they can, in such liquid state, readily be poured into the interspace between the frame and tube wall. The liquids solidify very rapidly (within approximately 5-20 minutes), without appreciable shrinkage, and form a firm contact mass between the frame and tube wall. Thanks to the mentioned additives, the filler masses are relatively insensitive to water and water vapors and, above all, will not produce any objectionable volatilization. It is particularly advantageous to provide the solid additives mentioned above, namely, the cuttings or shavings, with the sand being especially suitable because it is substantially insensitive to the temperatures to which the tube is subjected during the manufacturing stages. Furthermore, the sand will not produce any vapors or gases.

It has also been found desirable to mix a filler mass consisting substantially of sand with a binder, which, under appropriate treatment, solidifies and thus firmly binds the sand particles to each other so that, upon setting of the binder, the filler mass will be a solid mass consisting of sand and binding agent. The thus-obtained solidified filler mass produces the desired rigid connection between the frame and the tube.

The sand is, suitably, first cleaned and dried. The binding agent can be, for example, synthetic resins, wax, or the filler masses according to the present invention. The binding agents can be hot or cold setting agents; also, the binding agents can be in liquid or powder form. It is also possible to fill the interspace between the tube and frame entirely with pure sand, in which case, however, a good sealing compound or grouting will have to be provided at the edges of the frame. In practice, it is better if the sand has a binder homogeneously admixed with it.

The implosion protective device according to the present invention can be manufactured as follows: The sand is admixed with a powdered binder, which mixture is then introduced into the interspace between the frame and the tube, whereafter the mass is treated in such a manner as to melt the binder so that the latter firmly binds the sand particles.

Alternatively, the sand can be soaked in a liquid binder, as, for example, a synthetic resin solution of low viscosity. Here it is possible either first to pour the binder into the interspace and thereafter to introduce the sand, or first to let the sand flow into the interspace and thereafter to let the binder soak into the sand.

According to another method, the sand can be wetted with a liquid binder and then dried, whereafter the fragments obtained in this manner are reduced to small pieces and screened, the thus-prepared sand then being introduced into the interspace. The mass is then set generally by heat treatment. The sand is suitably very fine-grained (the grain size being of the order of approximately 400- 2000 microns) so that it can be trickled into the interspace. A better fill factor may be obtained if the sand has different size grains.

In the methods in which the sand is mixed with a liquid binder, a large quantity of binder will generally be needed in order completely to fill the interspaces between the individual sand particles. If the protective device is made by a method in which the sand is first appropriately prepared, i.e., a method in which the surfaces of the sand particles are powdered or coated with the binder and thereafter introduced into the interspace between the tube and frame, a subsequent heat treatment will cause the prepared sand particles to be bound to each other. This method, too, will produce a relatively rigid mass which, however, has air pockets and therefore contains a low proportion of binder. It is possible, in this way, to make do with approximately 4% binder. It is also possible to influence the setting time of the binder by appropriately heating the sand.

A main advantage of the described filler masses are to be seen in their resistivity against moisture. The disadvantages of gypsum and cement consist in the fact that these materials need much water to become liquid enough for pouring into the interspace. After gypsum or cement is in the solid state it needs much time to eliminate the water out of the solid filler mass. Furthermore cement often becomes chappy.

It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

What is claimed is:

1. An implosion protective device for cathode ray tubes comprising a rigid frame encompassing the tube in the region of its maximum diameter and being spaced from the wall of the tube, so as to form an interspace therebetween, and a set filler mass in said interspace, said filler mass being a material which remains solid up to a temperature of at least 80 C., which is highly liquid at temperatures of between approximately 100 C. and 180 C., which, while in solid state, does not volatilize to produce odorous or corrosive vapors, which sets quickly, and whose volume remains substantially unchanged as it goes from liquid to solid state.

2. A device as defined in claim 1 wherein said filler mass material is highly liquid at temperatures of between approximately 135 C. and 150 C.

3. A device as defined in claim 1 wherein said filler mass material is resistive to water and water vapors.

4. A device as defined in claim 1 wherein said filler mass material contains color pigmentation.

5. A device as defined in claim 1 wherein said frame has an edge configured to outline the viewing screen of said tube, there being a sealing ring made of cementing material arranged between said edge and said tube.

6. A device as defined in claim 1 wherein said filler mass material consists of urea having at least one additive.

7. A device as defined in claim 6 wherein said filler mass material has added to it wax, kieselguhr, and an acid selected from the group consisting of salicylic acid and benzoic acid.

8. A device as defined in claim 1 wherein said filler mass material consists of bitumen and an additive selected from the group consisting of wax and synthetic resins.

9. A device as defined in claim 1 wherein the filler mass material consists of hardened colophony and a softening agent.

10. A device as defined in claim 1 wherein said filler mass material consists Of Chlorinated naphthaline.

11. A device as defined in claim 1 wherein said filler mass material consists of solidified sugar.

12. A device as defined in claim 1 wherein said filler mass material consists of alum.

13. A device as defined in claim 1 wherein said filler rnass material consists of phthalic anhydride.

14. A device as defined in claim 1 wherein said filler mass material consists of betanaphthol.

15. A device as defined in claim 1 wherein said filler mass material consists of chlorinated polyethylene.

16. A device as defined in claim 1 wherein said filler mass material consists of parafiin and wax.

17. A device as defined in claim 1 wherein said filler mass material has solid cuttings admixed with it.

18. A device as defined in claim 17 wherein said cut tings are selected from the group consisting of wood pulp, porcelain powder and sand.

19. A device as defined in claim 17 wherein said cuttings are distributed substantially homogeneously through out said filler mass.

20. A device as defined in claim 1 wherein said filler mass contains air pockets.

21. A device as defined in claim 1 wherein said frame is made of metal.

22. A device as defined in claim 1 wherein said frame is pre-fonned and is made of a polyester glass fiber mixture.

23. A device as defined in claim 1 wherein said frame is made of a single piece.

24. A device as defined in claim 1 wherein said frame is made of a material selected from the group consisting of metal and plastics, and wherein said frame comprises two interconnected flanged parts.

25. An implosion protective device for cathode ray tubes comprising a rigid frame encompassing the tube in the region of its maximum diameter and being spaced from the wall of the tube so as to form an interspace therebetween, and a set filler mass in said interspace, said filler mass being selected from the group consisting of sand, a mixture containing at least 20% sand, and a material which remains solid up to a temperature of at least C. which is highly liquid at temperatures of between approximately C. and C., which while in solid state, does not volatilize to produce odorous or corrosive vapors, which sets quickly, and whose volume remains substantially unchanged as it goes from liquid to solid state.

References Cited UNITED STATES PATENTS 227,389 5/ 1880 Sawyer 2202.1

503,108 8/1893 Bates .1 220-21 1,647,695 11/ 1927 Hawley 264-261 2,091,615 8/1937 Rohm et al 264-261 2,500,384 3/1950 Schell 220-2.1 2,671,822 3/1954 McMahon 264-261 2,785,820 3/ 1957 Vincent et al.

OTHER REFERENCES German printed application, Philips, 1,117,158, Nov. 16, 1961.

THERON E. CONDON, Primary Examiner.

GEORGE O. RALSTON, Examiner.

M. L. RICE, Assistant Examiner.

Claims

1. AN IMPLOSION PROTECTIVE DEVICE FOR CATHODE RAY TUBES COMPRISING A RIGID FRAME ENCOMPASSING THE TUBE IN THE REGION OF ITS MAXIMUM DIAMETER AND BEING SPACED FROM THE WALL OF THE TUBE, SO AS TO FORM AN INTERSPACE THEREBETWEEN, AND A SET FILLER MASS IN SAID INTERSPACE, SAID FILLER MASS BEING A MATERIAL WHICH REMAINS SOLID UP TO A TEMPERATURE OF AT LEAST 80*C., WHICH REMAINS SOLID UP TO A TEMPERATURES OF BETWEEN APPROXIMATELY 100*C. AND 180* C., WHICH, WHILE IN SOLID STATE, DOES NOT VOLATILIZE TO PRODUCE ODOROUS OR CORROSIVE VAPORS, WHICH SET QUICKLY, AND WHOSE VOLUME REMAINS SUBSTANTIALLY UNCHANGED AS IT GOES FROM LIQUID TO SOLID STATE.