DE2408393A1 - COLOR TUBE - Google Patents

Description

Patent attorneys

Dr. Ing. H. Nogcr.denk didl Ina. H. Hauck ■? 1ρΓ P-; s. W. Schmitz Dipl. Ing. E. Gratis- -Ci,?!. Ir.g. W. Wehnert Hitachi Limited 8 ~ MüaJien 2. Mozsrtslraee 25

Telephone 5380586 5-1,1-chome, Marunouchi

Chiyoda-ku, Tokyo 2o. February 1974

Japan Legal File M-2992

Color picture tube

_; The invention relates to a color picture tube, and in particular ^! on the appearance of the front shell of a color picture tube. As is well known, the bulb of a color picture tube has an electron beam

Cannon assembly receiving neck, an adjoining funnel and one placed on the widening funnel end Front shell on. The front shell is chi ent with a fluorescent substance!

provided on its inner surface, the phosphor layer ι in turn from one to the end portion of the funnel at the end

: I.

the front shell extending metal layer is covered. The outside

The circumference of the front shell is provided with a reinforcing metal body to increase the mechanical strength of the tube piston and to prevent an implosion of the tube.

In many color picture tubes, the front edge of the ver j

strengthening metal body essentially along a curved j

Surface of the front shell, the metal body being the front shell j encased except for the effective screen area.

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In the case of a color picture tube for so-called push-through installation, the reinforcing metal body is designed to be narrower and encases one Section of the front shell that is closer to the funnel. In this tube, the curved front shell surface is at the end portion the front shell consequently only, so that this section lying outside the effective screen area is easily exposed to the view is. The use of such a color picture tube has the advantage that the visible area of the screen can be enlarged, because the front shell front can be arranged protruding from the housing. The costs can also be reduced because there is no Shield is needed. On the other hand, however, results in an undesirable appearance due to the exposed end portion of the front shell the tube. This means that the phosphor layer and the aluminum layer are visible from the outside. It is especially for usually difficult, the edge of the phosphor layer or the aluminum layer on the inner surface of the front shell evenly to train. Typically, both layers are very irregular, similar to a coastline on a land-

ikarte. This irregularity also results in an area the light is unevenly due to secondary electrons or electrons coming from overreaching too far ! emitted. In addition, the gloss changes due to the irregular appearance Edge of the aluminum layer on the inner surface of the : Front shell so that the tube slightly uneven appearance may have. Due to the reasons mentioned above, the appearance of the end section of the front shell suffers enormously. This disadvantage This is particularly noticeable with the black matrix tube for through-plug installation. Such a tube has one

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complicated two-layer structure consisting of a graphite layer and consists of a phosphor layer so that the irregular edges of these layers give an uneven gloss and very deteriorate the appearance. It has already been suggested forming the graphite layer close to the funnel; Yoke even in this case would result in the uneven distribution of thickness the graphite layer can be emphasized by the brightness of the fluorescent material when the tube is in operation, so that the unsightly appearance is not eliminated.

Even with this tube, the above-mentioned, irregular light emission of the phosphor is over the inner surface of the Edge portion of the front shell outside the effective area as a result of the secondary electrons or that of one that reaches too far Scan originating electrons seen from a certain position remote from the picture tube. So the appearance suffers. '

The invention is therefore based on the object to provide a color picture tube '■ that both looks nice in operation and out of operation. ;

According to the invention, a glass-like, opaque layer is on; the inner and / or outer surface of the front shell and j provided at least in a region between the effective Leuchtstoffflächb and the surface on which the reinforcing metal body \ is arranged to the irregular edges of the phosphor layer and the metal layer to the eye of a screen observer to

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to withdraw.

In an advantageous manner, a color former can be provided in the glass-like, opaque material, with which a beautiful Appearance of the tube is achieved and with which the commercial value of the tube increases.

The invention will now be explained in more detail with reference to the accompanying figures. Show it:

Fig. 1 is a longitudinal section through a tubular piston of a known

: Color picture tube,

jFig. 2 shows a longitudinal section through a tubular piston of another

! known color picture tube for push-through installation, Figure 3 shows part of the edge portion of the front shell of a color;

picture tube for push-through installation and Fig. 4 is a section through a front shell of an Invention according to color picture tube.

The tube piston of the picture tube shown in Fig. 1 has a neck 1 receiving an electron beam gun assembly, a funnel 2 extending therefrom and a front shell 3 placed on the open end of the funnel. The inner surface of the Front shell 3 is covered with a phosphor layer 4, which in turn is covered by an aluminum layer 5. The aluminum layer also extends over an end portion 31 of the front j

shell 3 and ends near the funnel 2. On the outer circumference of the front

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shell 3, a reinforcing metal body 6 is provided to increase the mechanical strength of the piston. The metal body 6 can be formed from so-called edge bands, which are fastened with a so-called tensioning band, or from a so-called shell, in which case a resin can then be provided between this shell and the front shell 3 which tries to expand during its solidification. 2 shows the tube piston of a push-through type picture tube protruding from the housing of a television set. In this figure, the parts corresponding to those in FIG. 1 are provided with the same reference numerals. A difference between the two types of tube shown is the arrangement of the reinforcing metal body on the front shell of the tube. As already indicated, was the front cover is in a built-in picture tube according to Fig. 2 further out of the housing, it äs the case with an ordinary tube. Consequently, as shown in Fig. 2, the metal body 6 is closer than in the case of the ordinary one; The picture tube in FIG. 1 is arranged on the funnel 2 over a section of the front shell 3. As a result, the outer side section 32 i

Part of ;

the front shell 3 in Fig. 2 free, which corresponds to a / metal body 6 in Fig. 1 sheathed portion. On the other hand, it is very difficult to apply the phosphor layer 3 and the aluminum layer 4, evenly on the inside of the front shell, and their edge lines are as complicated as the coastline on a map (see Fig. 3). This condition can be seen from the outside through the side section 32 of the front shell, including:

the appearance suffers a lot.

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In FIG. 3, the parts corresponding to those in FIGS. 1 and 2 show also have the same reference symbol.

Fig. 4 shows the front shell of a picture tube according to the invention. In this figure, too, those in FIGS. 1 to 3 corresponding Parts are provided with the same reference symbol. According to the invention, opaque material layers 3o are both on 'on the inner as well as on the outer surface of the front shell

applied to their side section, which may make the appearance the impairing area is covered. The front [edge of these material layers 3o extends outside the effective Area of the front shell.

The material used to form this opaque layer is a vitreous substance, which consists mainly of PbO and also contains B ^ O ,, ZnO and SiO ₂ , and metal oxides as color formers' such as MnO ₂ and Co 0 .. These substances are pulverized and uniform mixed and then suspended in a suitable solution.

The suspension produced in this way is dark in color. The suspension is then applied to the specific section applied to the front shell and heated, making the opaque Layer is formed.

In one embodiment, the suspension was made up of a mixture of 80% (parts by weight) of the materials listed below and made from 2ol binder, made from amyl acetate and Nitrocellulose.

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Components of the suspension

PbO

^B 2 ° 3 ZnO

^CO 2 ° 3 residues

Weight percent

7o%

15%

7%

5%

3%

correspond to the contamination.

Jic the above mixture was then applied to the side section of the front shell and heated to a temperature of about 45o C for about 1 hour to form the opaque layer.

Cu_0 and S can be used as color formers instead of MnO- and Co-O- will. In this case, the proportion of color formers used as substitutes should be smaller than in the above example. A A satisfactory result is obtained with 0.3% Cu “0 and 0.2% S. The temperature should be raised to approx. 600 ° C. during this process.

In either case, the resulting opaque layer exhibits a dark color.

If in another embodiment the vitreous material can provide sodium ions for the layer, then it is possible! lih, using AgCl and heating a yellow layer perm obtain. The yellow layer is essentially like the impenetrable! visible layer 3o used.

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Although some effect by forming the opaque layer either on the inner or on the outer surface of the side section of the front shell can be expected, the effect of the opaque coating is reduced, if this is only applied to the outer surface of the usual push-through tube.

Of course, the invention can also be used for other cathode ray tubes be used as picture tubes.

j As has been shown, with the help of the invention, the unequal

moderate edge quality of the fluorescent layer and the aluminum

■ layer or the graphite layer and an undesired light emission can be made ineffective by the phosphor layer, so that a clean appearance of the picture tube can easily be obtained.

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Claims (4)

Patent attorneys Dr. Ing.H. Necendank Ing.H. Touch - Dipi. Pn- _; 3. W.Schmitz l. Ing. E. Gr = s! F3 - Dipl. Ir.g. W. Wehnert Hitachi Limited ⁸ Munich 2, E £ ozarts £ rafie 25 Telephone 5380586 5-1,1 -chome Marunouchi Chiyoda-ku, Tokyo February 19, 1974 Japan Legal File M-2992 Claims ./Color picture tube with a neck, a funnel extending from the neck , a front shell placed on this, on the inner surface of which a phosphor layer and on top of it a Metal layer is applied, and with a reinforcing metal body surrounding the circumference of the front shell, characterized in that that the color picture tube on the inner and / or outer surface of the peripheral portion of the front shell (3) an opaque layer (3o), the peripheral portion between the effective fluorescent surface and that of the reinforcing metal body (6) is located sheathed surface. 2. Color picture tube according to claim 1, characterized in that the opaque layer (3o) is formed inter solidification of a suspension, one mainly of a vitreous Contains substance and composition containing a color former. 409849/0682 - 1o - 3. Color picture tube according to claim 1, characterized in that the opaque layer (3o) consists of a pias-like substance • is built up and has a color that "" solidifies of the vitreous substance results from the reactions of ions contained in the vitreous substance. 4. color picture tube according to claim 1, characterized in that the opaque layer (3o) extends such that the entire front part of the front shell is covered except for the effective fluorescent surface. AÜS849 / 0682