EP0643412B1 - Identification pattern for image tube components - Google Patents

Abstract

It is known to provide image tube components with identification patterns. According to the prior art, this identification of image tube components is carried out in such a manner that there are applied on the outside of the glass troughs (10) layers or labels which are particular to the cone and contain the identification data. Due to the additional layers or labels, this technique is, however, exceptionally costly, so that the object consisted in simplifying this method. According to the invention, it is specified to form the respective identification pattern (16) directly in a first function layer which is supported on the inside (19) of the respective image tube components. The method can be carried out in a particularly simple manner when the respective identification pattern (16) is burnt into the first function layer with the aid of the laser. <IMAGE>

Description

Technical field

The invention relates to identification patterns for picture tube parts formed from glass, which are subjected to a heat treatment in the manufacturing process, and to a method for marking picture tube parts.

State of the art

It is known to provide glass tubs of picture tubes with markings to simplify the manufacturing process, which allow the respective type of the glass tub or also a respective glass tub to be recognized. The glass trough forms the part of a picture tube that later faces the viewer when assembled.

A known way of realizing such markings is that the respective glass tub is provided with a label on its outside. According to US Pat. No. 4,374,451, a label provided with printed information is glued to the glass pan for this purpose. In view of the temperature processes which the glass trough has to go through in the course of its production, it is easy to see that such a solution does not guarantee reliable and permanent marking of picture tube parts. For this reason, the document DE 38 25 846 also specifies an adhesive label which has an identification image made of glass solder. If this label is stuck to the outside of the glass pan and runs through it Glass pan then a temperature process, so the identification image combines with the glass of the tub to a permanent and no longer removable identification.

If, however, a large number of different types of picture tubes are manufactured on a production line, it is perceived as a disadvantage when using labels that a corresponding number of labels must also be kept in stock for the different tube types, since it would be unreasonable effort to present such labels immediately before connecting to the glass tub. For the last reason, the variety of information on such labels is also limited.

Furthermore, it is known to provide electron beam systems of picture tubes with corresponding identification patterns. According to FR-A-2 517 116, it is stated to structure a conductive layer, which covers one of the surfaces of the glass strips connecting the various gratings of the system, for the purpose of identification.

However, since the conditions and requirements for the later readability of identification patterns on picture tube cones and picture tube trays are completely different from those in electron beam systems, such picture tube parts are marked according to the prior art (US 4,327,283) in such a way that at least one on the outside of the respective picture tube part area formed from glass frit material. Depending on the procedure, either the marking in the form of a machine-readable bar code is then formed in the Area created and then the created area fried with the glass pan or vice versa. The bar code is designed in such a way that the glass frit material applied there is partially removed again by using suitable measures on predetermined areas of the additionally formed area. Measures that are suitable for removing the glass frit material are mechanical and chemical processes including laser technology. In addition, it is known from US Pat. No. 5,214,350 to use the frit seam between the picture tube front plate and the picture tube cone for identification. For this purpose, a marking pattern is made from an additionally applied pigment material on the surface of the frit seam, which faces the picture tube front plate, which is then visible through the glass of the picture tube parts after frying the two picture tube parts.

Although an individual marking of each glass trough can be carried out by means of this method, it is considered disadvantageous, however, that with this type of marking at least one layer, which is not required for the pure production of picture tubes, must always be produced on the glass trough in several working steps. As the US Pat. No. 4,600,630 emphasizes in this context, for reasons of legibility, a bar coding created according to the US Pat. No. 4,327,283, it is necessary to protect the marking from contamination by means of a special protective layer.

As tests by the applicant have shown, a direct marking, that is to say incorporated into the surface of the screen glass, cannot be carried out, since - as is also indirectly confirmed by the document US Pat an inadmissible weakening of the (shield) gas pan, which is later under considerable load when assembled.

The invention is therefore based on the object of specifying markings of picture tube parts, the production of which does not require any layers / materials which go beyond the production of the respective picture tube part and is also protected against external influences.

Another object of the invention is to provide a method for producing markings for picture tube parts, which makes it possible to produce marking patterns for picture tube parts in a very simple process, safely and protected against external influences.

Presentation of the invention

The first object is achieved according to claim 1 in that the identification pattern of the respective picture tube part is formed on the inside thereof and is formed from a secondary arrangement of functional layers which are at least in the area of the identification pattern and which lie directly on the inner surface of the respective picture tube part and are necessary for the operation of the picture tube. The design of the identification pattern on the inside of glass trays is also particularly advantageous because it does not hinder the later mounting of the so-called implo frame over the outer contour of the glass tray.

What is understood by the first functional layer in the sense of this application is defined in claim 2. Is the glass tub the part of the picture tube which is to be identified is the functional layer either the internal mirroring made of aluminum or the black matrix layer. In this context, it should be pointed out that in the case of black matrix tubes in the edge region of the glass troughs, the layer lying directly on the inside of the trough is the black matrix layer. This black matrix layer is coated on the side facing away from the glass of the picture tube part with the internal mirroring when the glass tub has been completed. If the first functional layer in black matrix tubes is to be the internal mirroring, it must be ensured that the areas of the troughs which are to have the identification image are no longer coated with black matrix material when the internal mirroring is applied in a subsequent step .

If the picture tube cone is the picture tube part to be identified, then the so-called inner conductive layer is the first functional layer of this picture tube part. A particularly good contrast of the identification image is achieved if, according to claim 3, the free areas formed in the first functional layer are covered with a further functional layer which takes a high contrast to the material of the first functional layer. If the areas free of the first functional layer are formed in the black matrix layer, a high contrast is achieved when these free areas are covered by the internal mirroring. If the areas free of the first functional layer are formed in the picture tube cone, equally good contrast ratios can be set if the free areas are arranged in the first functional layer (here the inner conductive layer) near the getter. Will this narrow spatial If the relationship is maintained and the getter is activated later, the silver barium mirror is deposited on the surfaces free of the inner conductive layer.

The second object is achieved according to claim 4 in that the identification patterns are formed during or after the formation of the first functional layer on the inside of the respective picture tube part by forming areas which are not covered by the first functional layer and these areas with a further and for the production of the respective picture tube part anyway required functional layer are coated. If the first functional layer is formed, for example, by a black matrix layer, good contrast ratios are achieved by applying the further functional layer in the form of the internal mirroring.

How the free areas are formed in the first functional layer is in principle at the discretion of the person skilled in the art, provided that it is ensured that this does not cause damage or change to the glass or the glass surface of the respective picture tube part.

However, if, according to claim 5, the free surfaces ultimately forming the identification pattern are created in the first functional layer by means of a laser in this layer, this has the advantage that particularly sharp-edged identification patterns are formed. This is particularly important if bar coding is selected as the identification pattern.

A particularly simple procedure is according to Claim 6 given when the laser generates the surfaces free of the first functional layer through the wall thickness of the respective picture tube part formed from glass. The latter because often the placement of the laser arrangement within the respective picture tube part is often ruled out for reasons of space.

If a laser is used to burn in the free areas in the first functional layer, the wavelength of the laser is approximately 1.06 μm and the power is between 15 and 60 If the distance between the laser head and the plane of the first functional layer is about 20 cm, there is no fear that the laser will cause changes in the glass of the picture tube parts.

Brief presentation of the figures

Figur 1

Schnitt durch eine Glaswanne einer Bildröhre;

Figur 2a und 2b

Seitenansichten einer Glaswanne von einer Bildröhre; und

Figur 3

eine Vorrichtung zum Herstellen von Kennzeichnungsmustern (schematisch).

Show it:

Figure 1

Section through a glass tub of a picture tube;

Figure 2a and 2b

Side views of a glass pan from a picture tube; and

Figure 3

a device for producing identification patterns (schematic).

Ways of Carrying Out the Invention

The invention will now be explained in more detail with reference to the figures.

FIG. 1 shows a section through a picture tube part in the form of a glass trough 10. This glass trough 10 is covered on its inside 19 facing away from the viewer with phosphor strips 11 which emit light under the action of electron beams (not shown). In order to improve the contrast, the distance between the mutually adjacent phosphor strips 11 is filled with a light-absorbing material 12. Such a type of shielding the inside of glass tubs 10 is also commonly referred to as a black matrix structure. On the out The so-called internal mirroring 13 is formed for the phosphor strip 11 and the light-absorbing material 12. The inner mirroring 13 is a metal layer, which preferably consists of aluminum and is formed on the inside of the glass trough using an evaporation process.

For the sake of completeness, it should be pointed out that, before the internal mirroring 13 is applied, the surface to be vaporized is still prepared by using at least one painting step. This lacquer layer, which would still be recognizable in the production stage shown in FIG. 1 between the internal mirroring 13 and the layer formed from fluorescent strips 11 and light-absorbing material 12, is not shown for reasons of clarity.

A raised edge 14 adjoins the area of the glass trough 10 which is provided with fluorescent strips 11 and the light-absorbing material 12. The surface 15 of this edge 14 is later connected to the cone of the picture tube (not shown). The coating sequence on the inside 19 of the glass trough 10 in the edge area 14 is largely similar to that which has already been explained in connection with the inside facing away from the viewer. In contrast to these statements, however, there is no longer any phosphor 11 in the edge region 14, but the light-absorbing material 12 almost completely covers the inside 19 of the glass trough 10. From the inside 19 of the edge region 14 coated with light-absorbing material 12, only one surface 17, which receives the identification image to be produced later, is excluded. As can be clearly seen from FIG. 1, the area 17 lies in the area Internal mirroring 13 directly on the surface of the glass of the glass trough 10 and forms the first functional layer in the exemplary embodiment shown here. The marking pattern 16, which can be created according to the manufacturer's individual specifications, can be formed on the surface 17, as illustrated in FIG. 2a, by removing the internal mirroring 13 down to the surface of the glass of the glass trough 10.

In principle, it is irrelevant which measures the person skilled in the art takes to remove the internal mirroring 13 or to form the identification pattern 16, provided that the use of such methods leaves the glass structure itself unchanged. For example, only the scraping of the internal mirroring 13 should be mentioned here as a mechanically acting method. However, if particularly sharp-edged identification patterns 16 are to be produced, such as are necessary, for example, to ensure the machine readability of bar codes (shown in FIG. 2a), it is particularly advantageous to create such identification images 16 using a laser. Which measures must be taken into account when using laser technology will be discussed in detail later.

In addition, however, it should be pointed out that the identification pattern 16 can also be formed in the interior mirroring 13 by the fact that the areas free of the interior mirroring 13 and ultimately forming the identification pattern 16 in the interior mirroring 13 by applying suitable masking measures at the same time as the application of the interior mirroring 13 can be generated.

A labeling pattern 16 is shown in plain text in FIG. 2b. In contrast to the representations according to FIGS. 1 and 2a, according to FIG. 2b, no layer of light-absorbing material 12 is formed on the inside 19 of the glass trough 10. It is therefore not necessary in the case of glass trays 10 produced in this way to form a surface 17 free of light-absorbing material 12 on the inside of the edge region 14 of the glass trough 10, since after vapor deposition with aluminum, for example, the internal mirroring 13 is in any case directly on the surface of the glass trough 10 in the edge region 14 rests. Thus, according to the exemplary embodiment according to FIG. 2 b, the respective identification image 16 can be formed in the edge region 14 during or after the application of the internal mirroring 13 to the inside 19. The latter method procedure is also possible with black matrix structures discussed in connection with FIGS. 1 and 2a, if it is ensured that the entire inner surface of the edge region 14 is not made of this material when the layer formed from light-absorbing material 12 is formed 12 is coated.

The glass trough design according to FIG. 2b is also not limited to identification pattern 16 in plain text. Rather, in cases in which the entire inner surface of the edge region 14 is provided with the internal mirroring 13, it can be created with a marking image 16 in bar coding, as is shown in connection with FIG. 2a.

As already explained above, it is particularly advantageous to create the respective identification pattern 16 with a laser. Because it was extremely stressed in the case of glass tubs 10 assembled from picture tubes Components are involved, it must be ensured when using the laser technology that when the identification pattern 16 burns out, the structure of the glass pan 10 does not undergo any changes. This is relatively easy to implement if the laser beam strikes the interior mirroring 13 from the inside of the glass trough 10. Such a procedure is only conditionally possible due to the limited space inside the tub 10. Therefore, if the design of the identification pattern 16 is to be burned from the outside through the thickness of the glass into the internal mirroring (represented by the arrows P in FIGS. 1 and 3), special conditions which prevent the gas from being exposed to heat at the burn-in point must be set. This is particularly difficult with regard to the types of glass required for the production of glass tubs 10 because these glass tubs are not transparent and also contain admixtures of, for example, Br, Ca, Li and Sr in the glass. Furthermore, the focusing in the case of lasers guided through the glass thickness is not uncritical because the inside of the glass trough 10 has a defined roughness for improving the adhesion of the layers applied to the inside of the glass trough 10.
However, these problems are solved when a writing laser with a wavelength of 1.06 μm and a power between 15 and 60 watts is used and the distance a between the laser head 18 and the plane of the inner mirroring 13 to be labeled is approximately 20 cm (FIG 3). Laser devices that meet these performance data are available on the market and can be obtained, for example, from the manufacturer Haas-Laser GmbH, Schramberg under the name Hass 6211. If the identification image 16 is created using laser technology, an identification image created in this way can 16 a very high amount of information can be added without the ongoing production being hindered by the execution of the marking.

In addition, it should be pointed out that the burning in of a marking image 16 by means of a laser arrangement does not necessarily have to be carried out in one step. Rather, in the formation of bar-coded identification images 16 (FIG. 2a) to increase machine readability, it is very advantageous to develop such identification images in two steps by first removing the areas to be removed and forming the identification image from the laser arrangement, and then in a second step, the contour of the areas that were removed in the first step are reworked with the laser arrangement to increase the edge sharpness.

In the exemplary embodiment explained in connection with FIG. 1, after the glass trough 10 has been coated with the light-absorbing material 12, the surface 17 has been freed from the material 12 or has already been kept free of material 12 during the coating by using suitable covering measures. By using the laser technology described above, for example, this measure is no longer necessary. If the upstanding edge of the glass pan 10 is completely coated with light-absorbing material 12 and the glass pan 10 is fully shielded with phosphor 11, the identification image 16 can also be burned directly into the light-absorbing layer 12 in the edge region of the glass pan 10 by using an inclined laser. In this case, the layer 12 forms the first functional layer of the glass trough 10 After the branding image 16 has been burned in, if the entire glass trough 10 is provided with the internal mirroring 13, the aluminum of the internal mirroring 13 strikes directly in the area in which the marking image 16 was burned out in the layer 12 on the burned-out surfaces on the inside 19 the glass pan 10 on the glass surface. Since this identification image 16 is formed by a sequence of light-absorbing material 12 and inner seal 13, the identification image 16 is very easy to read because of the good contrast that it provides.

Furthermore, it is pointed out that picture tube cones (not shown) can also be marked very easily. This can be achieved in that during or after the application and drying of the so-called inner conductive layer, the identification image 16 is formed in the inner conductive layer (= first functional layer of the cone) by creating free surfaces from the inner conductive layer in the inner conductive layer for producing the identification pattern 16. Here too, the identification image 16 can be burned out by means of a laser in the inner conductive layer of the cone. Since the sequence of free-burned and non-free-burned areas in the brownish-red inner conductive layer is difficult to recognize from the outside, the legibility of the coding in the picture tube cone is brought about by covering the free-burned areas in the inner conductive layer with a silvery barium mirror, which is anyway used in the production of picture tubes arises by activating the getter to remove residual gases in the vacuum of the finished picture tube. Since the barium level however only in a spatially narrow area around the getter, it is necessary to ensure good contrast ratios that the burn-in locations for the identification image 16 are arranged in the inner conductive layer in the immediate vicinity of the getter.

Claims (7)

1. A picture tube component composed of glass with an identification pattern and with at least one function layer (12, 13) which is applied to the inside (19) of the respective picture tube component (10) and is essential for the operation of the picture tube,
   characterised in that the identification pattern (16) is formed by the juxtaposition of two different function layers (12, 13) on the surface of the respective glass component.
2. A picture tube component according to Claim 1, characterised in that the first function layer is the black-matrix layer (12) of the glass trough (10) or the inner conductive layer of the picture tube cone.
3. A picture tube component according to Claim 1 or 2, characterised in that relative to the black-matrix layer (12) the second function layer is the inner reflective coating (13) of the glass trough (10) and relative to the inner conductive layer of the picture tube cone it is the barium reflector which is formed with the activation of the grid.
4. A process for identifying picture tube components made of glass with function layers (12, 13) which are arranged on the inside (19) of the respective picture tube component (10) and are essential for the operation of the picture tube, characterised in that during or after the formation of a function layer (12) which adheres directly to the inside (19) of the respective picture tube component (10), surfaces are formed which are free of this first function layer (12) and that the surfaces which are free of this first function layer (12) are covered with a further function layer (13) which moreover covers the surface of the first function layer (12).
5. A process according to Claim 4, characterised in that the surfaces which are free of the first function layer (12) are formed by means of a laser by which the material from which the first function layer (120 is formed is burned away down to the glass of the respective picture tube component (10).
6. A process according to Claim 5, characterised in that the laser burns away the surfaces which are free of the first function layer (12) through the wall thickness of the respective picture tube component (10) made of glass.
7. A process according to Claim 5 or 6, characterised in that the laser has a wave length of approximately 1.06 µm and a power output of between 15 and 60 watt and the laser head maintains a distance of approximately 20 cm from the function layer (12) which is to be burned away.

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