DE1646240B1 - Forgery-proof image and writing-bearing surfaces - Google Patents

Description

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The invention relates to a layer structure with positive and negative dichroic substances in the

Help its information-carrying surfaces, such as image-common ground mass absorption axes,

and writing surfaces, made forgery-proof, which are perpendicular to each other,

can be. Any change or attempted change. The determination of whether it is positive or negative

The information-carrying surface can be changed with 5 negative dichroic substance, can

the layer structure according to the invention in a simple manner by measuring the optical density with in one

and be ascertained in a reliable manner. Determine plane polarized light. In this case

It has already been suggested that under "optical density" information is not the opposite of that

to make supporting surfaces tamper-proof by using different refractive

that they can be understood with an essentially transparent io index, but the extent of the absorption

Coating, which is light-polarizing, was provided in the two optical axes or the trans-

the. Unauthorized changes, damage and mission (intensity). Result from these measured values

Counterfeits of this coating could be identified with the help of the terms: positive dichroic and negative

of an analyzer. Dichroic in the analyzer. The optical density of a dye will

it is a polarizer, where the PoIa- 15 is first determined by the electrical vector

The direction of polarization is not the same as the direction of polarization (direction of oscillation) of the polarized beam

of the light polarizing coating. Light to the orientation direction of the plastic molecules

An improvement of these measures is parallel to the detection, this measured value is referred to as dij-

forgeries, changes and damage, analogously the electrical vector results perpendicular to the

of information-carrying surfaces is 20 Molecular orientation of the plastic d L ■ To now the

the problem to be solved according to the invention. The inventiveness of positive and negative dichroic

This means that it is common to use the λ

to use text-bearing surfaces with at least a light ratio of optical density. At "

polarizing coating on the basis of molecular- a ratio d || / dL> l becomes the dye

oriented polymers, especially polyvinyl 25 positive dichroic and with dj | / dL <l as negative

alcohol, and is characterized in that the denotes dichroic.

Coating one or more dye strips or The invention is based on the following phenomenon: -areas and the or the dye stripe If a positive and a negative dichroic color or -areas either two oppositely mixed materials of different colors are present, chroic dyes or an isotropic dye 30 e.g. B. in solution, the resulting color is the together with a dichroic dye under- adding the colors of the individual dyes, however of different colors. In place of the two, no dye loses its negative or positive opposite Dichroic dyes can also have dichroic properties. Is now a suitable double dichroic dye within the nicely oriented, clear plastic of the invention Provide cover. 35 material with a mixture of a positive and a

According to the invention, the counterfeit negative dichroic dye is dyed and the secure coating a positive and a negative dichroic area colored in this way in polarized table dye but an isotropic dye when viewed together- light whose direction of oscillation is parallel men with a positive dichroic or with one to the orientation direction of the plastic molecule negative dichroic for use. Where is 40, it is the original color of the positive dichroic Both color components can also be dominated by a table dye, while the urso-called double dichroic dye original color of negative dichroic color turning. Substance is essentially deleted. Will on the other hand

As is well known, dichroism is based on the property of different crystalline substances, composite, whose direction of oscillation is perpendicular to that of an incident light beam, depending on the direction of orientation of the plastic material, the direction of oscillation becomes differently strong The original color of the negative dichroic absorbing substance is called a dichroic dye, whereas one is a substance that shows a pronounced di- original color of the positive dichroic color chromism. The dichroic properties 50 substance is essentially dissolved.
Corresponding dyes are found in the invention. There are dyes that behave as positive as well as negative dichroic within a molecularly oriented art. Such sub-substance material. They show two axes that punch each other are called double dichroic. Are essentially at right angles, namely polarized light is of such dyes in the absorption axis and the transmission axis. 55 Two transmission components and two absorption If non-polarized light falls on such substances, it is split into a transmission component and a transmission component of different wavelengths. The transmission components are separated into the absorption component. The transmission axes are polarized, the sion component is perpendicular to each other in the plane of the transmission. If an axis is polarized accordingly, it is perpendicular to the absorbent 60-oriented transparent plastic material with an axis of movement. The absorption axis of a specific double dichroic dye and type of dichroic substance is located in one, this area is under polarized light with an angle of 90 ° to the absorption axis of another type of oscillation direction parallel to the orientation of dichroic substances when it is in a When looking at the direction of the plastic material, there will be a common ground mass. From the below a color is observed which corresponds to the wavelength of the different position of the absorption axes to one another, whose transmission axis parallel results in the designation positive-dichroic or negative-dichroic to the direction of orientation of the plastic material. In other words, wise comes to rest. Looking at the colored

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Area in polarized light with vibration aligner, the colors of the individual components slightly

direction perpendicular to the direction of orientation of the, these colors differing from the

Plastic material, the observed color corresponds to the mixture differ. It's obvious-

Color of the wavelength of the component whose trans- lent that information treated in this way

Mission axis perpendicular to the direction of orientation 5 bearing surfaces are unique because at least one

of the plastic material. If one now looks at the part of the surface with a very specific color

same area with unpolarized light, so it is colored, but with the naked eye as

this area appears in the color of the origin - a single color appears and when appropriate

borrowed dye, i.e. a color that easily separates the two when illuminated with polarized light Adding the two components results in. io different colors can be noted.

Essentially the same color effects can be achieved. As an analyzer, any source for polar-

using a mixture of isotropic dye-based light. Possibly the easiest

one color and one positive dichroic or method is an essentially transparent poly-

a negative dichroic dye an under-risator known in many species, e.g. B. Polar dissimilar Color, in spite of the isotropic dye 15 sation sun glasses. If one looks at an inventive

itself does not lead to polarization. In any case, according to the protected information-carrying area

If a correspondingly oriented, transparent aid of such an analyzer is shown, one observes

Plastic material even with the naked eye, depending on one of the colors of the two components

a single color, namely the color of the addition of whether the direction of oscillation is parallel or both dyes of the mixture. 20 perpendicular to the direction of orientation of the polarized

In the case of a mixture of an isotropic and a generating part of the coating on the information

positive dichroic dye and viewing area is. Now turn the analyzer by 90 °

rotated with polarized light with the direction of oscillation, the second color component appears,

perpendicular to the direction of orientation of the art In order to now avoid that when examining on Fabric material is the color of the positive dichroic integrity of the one equipped according to the invention

see the dye being essentially erased and the information-bearing surface permanently

only the color of the isotropic dye was observed. must be turned, it is probably more appropriate

However, using the same material in polarized light will apply a two-field polarizer. Here,

with the direction of oscillation parallel to the orientation, it is a flat, light-polarizing one considered direction of the plastic material, so 30 element of two fields or areas in the

you can see the material with the color of the original - same plane butt against each other and the

the mixture, however, is somewhat darker, i.e. with the directions of the two fields perpendicular to one another.

lower intensity. stand right.

In the case of a mixture of an isotropic and a negative dichroic The invention is intended to be more detailed with the aid of the figures Dye can be refined in polarized light 35.

with the direction of oscillation parallel to the orientation F i g. 1 shows in principle a two-field polarizer

direction of the plastic material appears to test the forgery-proof according to the invention

Color of the isotropic dye alone, and the color ren image and text-bearing areas with an or

of the negative dichroic dye is extinguished. With multiple coatings;

Viewing in polarized light with oscillation 4 ° F i g. Figure 2 shows an identity card with an overlay

direction perpendicular to the orientation direction of the in the form of essentially transparent, molecular

Plastic material appears the color of the original ocular-oriented polymer and a color stripe,

lent mixture darker. containing a positive dichroic dye and

So far, the phenomena of dichroism have ultimately become a two-field polarizer;

in connection with a molecularly focused 45 F i g. 3 shows an identity map, accordingly

Discussed plastic material. Of course, F i g. 2, but with a negative dichroic color

you can also use a different plastic material but strips of cloth;

also use glass, provided that it is at least F i g. 4 shows a modification of the identity cards

can be superficially oriented accordingly, from Fig. 2 and 3 by making the dye strip a

so that it is mixed with negative and positive dichroic 50 one positive and one negative dichroic

Can be colored by dyes. Contains dye;

If an oriented transparent film is now shown, FIG. 5 shows a modification of the invention

the at least part of the identity card prepared as indicated above according to FIG. 4, however

is colored, on information-bearing surfaces - as with a dye strip containing an isotropic

ID cards, identity cards, credit cards or the like - 55 pen dye;

raised, one achieves a high degree of F i g. 6 shows a prepared according to the invention

Safety. The fact that the cover is at least an identity card, the dye strip of which has an isotropic

partially a molecularly oriented light polarizing dye and a positive dichroic dye

Material is makes most of the changes of contains;

Coating like a cutting out and in the following 60 F i g. 7 shows the modification of the color stripe,

reinsert with the help of heat or a solution containing an isotropic dye and a negative

medium easy to determine. The colored light polar dichroic dye;

The area in which the process is based has a well-defined figure. 8 shows an identity system according to the invention

Color and intensity and therefore permits a sub-map with a double-dichroic color stripe

division in the information-carrying surface. Contains 65 dye.

It is much more important, however, that when considering F i g. 1 shows an analyzer for viewing

the information-carrying surface in polarized light-polarizing layers. According to FIG. 1 a

Light z. B. with the help of a light polarizing analyzer double field polarizer, d. H. a linearly polarized

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rendes material, with two areas in different- divided into the color components, the upper field

polarize borrowed directions. They can be 19 appears yellow and the lower field 20 blue,

is made from commercially available light-polarizing F i g. 5 shows a further modification, the

Substances such as iodine-containing, molecularly oriented poly dye strips an isotropic dye of a

vinyl alcohol plastics that contain polarizers based on 5-color, that is a non-dichroic

of cellulose or two Nicoische prisms, the shear dye. Looking through this strip

are connected to one another in a corresponding manner. the analyzer 11, both fields 22 and appear

A polarizer can also be identical to a dichroic 23 with regard to the colors. You also iden-

Dye be included. (The color of a table so colored to the color of the areas 12, as they are with the

As is easy to see, material will be able to be recognized by the naked eye. Of the

see the coatings affect, however the analyzer will show the colors however darker or darker

The intensity of the individual colored components is different, due to a certain light

be easily recognizable.) In F i g. 1 is now a debilitating effect of the analyzer itself.

Two-field polarizer with two polarization directions. In the embodiment according to FIG. 6 contains the

a mixture of a positive-di-

8 and 9. The direction of polarization of a chroic dye and an isotropic dye

of the two halves are perpendicular to each other. Fabric. If one uses, for example, as a positive-di-

When using the analyzer, a blue dye is applied to every chromic dye and, as is desired, a yellow dye is applied to the area to be observed. Examples of this are given in the following 20 upper and lower area 24 for naked eye figures. An analyzer in these turns green accordingly. However, if the dye streak is passed through the double-field polarizer of FIG. 1 applied. When looking at analyzer 11, the lower Λ appears

According to the Fi g. 2 to 8 an identity card field 26 became darker and more intense green. In the case of the upper ™ field 25 which is forgery-proof as an image and text-bearing surface, the color of the positive dichroic color is essentially eliminated according to the invention with a substance, so the field 25 does not appear green but yellow,
Kularoriented material is coated. In the embodiment according to FIG. 7, the coating has a specially colored strip of dye strip, a mixture of negative diauf, and the strip shown in FIG. 1 chroic dye and an isotropic color analyzer shown superimposed. For all figures 30 pieces of fabric. If, for example, a red dye is used as the negative direction of the polymeric material chroic dye and a yellow dye is used as the isodic coating perpendicular and parallel to the tropical dye, strips of fabric appear. the upper and lower areas 27 for unarmed

From Fig. 2 you take out the identity card 10 ne eye orange. Looking at the dye

with the overlay of oriented material which is grazing through the analyzer 11, so it appears

contains a color stripe, which is darker or more intense orange by a positive upper field 28, the

dichroic color is formed. With the unarmed lower field 29 by excluding the negative-di-

Neten eye appears the color stripe z. B. blue, and chroic dye but not orange, but

as in the figure with the upper and lower yellow.

ren parts 12 is displayed. When looking through the 40 Fig. 8 now brings in the dye strip

Analyzer 11 gives the following picture: The color situation with a single double dichroic

in the area of the upper field 13 is essentially dye of a certain color, for example

decreased or disappeared at all. This purple. The upper and lower areas 30 of the coloring

rests on the positive dichroism mentioned above. strips of fabric only appear t to the naked eye

The color of the lower field 14, on the other hand, is intense violet. Looking through the dye strip

However, due to the color-intensifying effect of the light analyzer 11, two separate ones are observed

polarizing analyzer and appears z. B. now and certain colors in fields 31 and 32,

deep blue. z. B. beige and blue.

The dye strip of Fig. 3 contains a coating on top of which is the polarizer

negative dichroic dye of e.g. yellow, such as 50 information-carrying surface according to the invention

erlin the region 15 at the upper or lower part can be any molecularly oriented, essentially

of the dye streak can be seen. When looking at it, be transparent material, which differs with

through the analyzer 11, the proportions of chroic dyes can be stained, as orientated

rade reversed to those of FIG. 2. The color of the tated polyvinyl alcohol, polyvinyl alcohol poly-

Lower field 17 of the analyzer is reduced or 55 vinylen, cellulose or glass. The dyes are

disappeared at all, whereas the color of the applied in a known manner, as z. Am

upper field 16 more intense z. B. deeper yellow where "vectography" is the case.

appears. Is it the colored areas of the

The color stripe of FIG. 4 contains a mixture of coating around strips, as shown in the figures

a positive dichroic dye and a 60 are placed, a solution of the color

negative dichroic dye of different substances or the double dichroic dye with

Colour. For example, if you use dyes, such as those applied with the help of a sponge or felt,

at the F i g. 2 and 3 have been mentioned, i.e. H. The colored areas can, if

positive dichroic blue and negative dichroic wishes to have a certain shape within the over-

Yellow, the upper and lower part of the 65 train appears to have. You can use a specific character

Dye strip 18 in the mixed color of blue and word or a representation. In such a

Yellow, namely green. If such a strip falls through, it is advisable to use the color

If the analyzer 11 is viewed, the mixture is applied directly to the oriented plastic coating

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printed using known methods. In addition it is The dye combinations that can be obtained by Mizur Improvement of the absorption capacity of the masking of negative and positive dichroic color lines for the dye in general necessary with substances can be obtained are relatively limited; it was caustic soda to mercerize or pickle. however, there is the option of using isotropic dyes

The way in which the transparent polarizing 5 either the positive dichroic dye or coatings are applied to the information-carrying surface on the negative dichroic dye depends on the respective polarizing material used and available to all colors of the spectrum partly of have. Any isotropic dye can be removed from the type of surface to be coated. Is z. B. turn, provided that it is used for staining the information-carrying surface made of metal, paper, io specially oriented base material wood or a wood product, so a number can or is included,
of pressure-sensitive adhesives available, such as As already mentioned, there are dyes that show such a double dichroism on the basis of butadiene-acrylonitrile mixed. So was z. B. observer polymers that pay attention to both the information-bearing that when staining or coloring a film surface as well as on the facing surface of the pola- 15 of a molecularly oriented polyvinyl alcohol with risierenden coating are applied. You can use a commercially available dye to make the film appear deep purple to the armed eye with, however, also adhesives based on epoxy resin. However, it will turn. In the case of thermosetting epoxy resin adhesives, the film is viewed through a polarizer, so it is important to ensure that one part is not royal blue and the other part beige,
to a disorientation of the polarizing material 20 identity cards, credit cards or the like. are properly made forgery-proof, can

According to the invention, an image-bearing surface is intended to be inserted into a protective cover or envelope

are protected, it means that usual photo-. At least one side of the protective cover is on

Graphics with a generally gelatin or transparent and shows the information-bearing

modified gelatin surface can be coated with the coating. Part of the transparent

should. The fixation of the polarizing cover term sheath or the dust jacket can be a

can with the help of a transparent pressure-sensitive double field polarizer over the color strip of the

borrowed adhesive. Have the card itself. In this way a

The measures according to the invention result in a direct analyzer. The different colors of the

Not only do the information-carrying layer in front of the felling become 30 individual components at the same time

This is secured and can be seen very quickly without the need for additional equipment.

covers, but there is also a separation of the infor- In this way, counterfeits not only can

The information-bearing layer can easily be recognized from behind by means of the color scheme, but is also

bar. In one embodiment for images, a change in the sequence of layers by a discount

the polarizer a hydroxylated polymer such as 35 nuity of the reflected light detectable. It will

Polyvinjrlalkohol, polyvinyl alcohol mixed polymer pointed out that the invention

acidified or hydrolyzed cellulose acetates. These coatings don't just have a single stripe or color

Layer may have to have a colored area but rather on the image with the help of an intermediate layer

layer in the form of a copolymer of methyl- also a multitude of colored areas of the same

vinyl ether and maleic anhydride applied 4 ° or different colors. So can

will. for example, an identity card with a

There are cases where the information-carrying surface is provided with a coating that is to be embossed in two or more colors with certain information; This strip of different colors according to the invention applies in particular to credit cards, where the name, address. The strips themselves can be different and code number should be embossed. Embossed dyes or dye mixtures or a common or embossable information-carrying surface can contain the same color together with a different color component, including the light-polarizing element. The following examples are created, they are therefore in the above-described the invention,
benen way made forgery-proof. In this _R. · 1 1
Case is preferably a flexible base of the 5 °. Example
Information-bearing layer such as paper or a dye liquor was prepared according to the following composite photograph, which was produced with a flexible, light composition: 30 g negative dichroic polarizing element, such as a polyvinyl alcohol dye acid dye »blue 170«, 2 g positive di polarizer film is connected. Another artificial chronic dye »Direct-red 117«, a transparent layer containing a substance, can be applied 55 28230 in 600 ecm of water. A polyvinyl alcohol can lead to better stability, edge film has been strengthened by stretching to 4 times its length, tear resistance and the like, even in the case of bean, and with a back film made of cellulose acetate, it results in stresses through embossing. Butyrate and intermediate layers of cellulose nitrate are suitable for this purpose, the known film materials made of poly- and cellulose nitrate-hydrolyzed polyvinyl alcohol, vinyl chlorides or mixtures or copolymers deposited. At a rate of about sate of polyvinyl chlorides and polyvinyl acetates. 1 m / min at a temperature of about 71 ° C

The polarizer according to the invention on the infor- this film coated with the dye liquor. It made up The mation-bearing surface can also not have a purple stripe through it. The area stained in this way polarizing, transparent layers covered was washed with a 1% boric acid solution and be coated; this is not only the case 65 and dried in vacuum at room temperature, if the layer structure is to be embossed. For this then at room temperature with a 10% poly propylene z. B. plastics such as polystyrene or glass vinyl alcohol solution coated and these getrockje according to the required flexibility of the objects. net.

A color photograph was taken by the diffusion transfer process. As long as this still was fresh and moist, it was pressed onto the polyvinyl alcohol film described above. To the layers were attempted to separate for about 5 minutes; however, it was found that the image adhered properly to the top layer.

Now the photographic protected in this way was colored neutrally with the help of a linearly polarizing one Polarizer with a transmittance of about 38% considered. The film was placed so that the The direction of polarization was parallel to the direction of orientation of the stretched polyvinyl alcohol film; well the dye strip, which is purple to the naked eye, appeared red. The polarizer film was twisted by 90 °, the color of the dye strip changed to violet and finally to blue. Looked at If you put the dye strip with a two-field polarizer, the upper part of the dye strip appeared red and was thus in sharp contrast ao to the lower part, which appeared blue.

The polyvinyl alcohol film was used on the stained surface prior to peeling onto the picture for complete uniformity of the secure connection between the top layer and the photographic one Image. Practically the same effect can be achieved if the picture surface or the top layer itself is included an aqueous solution of polyvinyl alcohol as a kind of varnish is moistened just before application. It should be noted that these measures are not absolutely necessary. A sufficient one Safety can also be achieved without this paint.

Example 2

The measures of Example 1 were repeated, but a dye liquor was used, the 5 g Acid dye "Yellow 152" as a negative dichroic dye and 1.5 g "Direct blue 1" color index 24410 as a positive dichroic dye dissolved in 200 ecm water and 50 ecm ethanol. The staining strip appeared green with the naked eye. With the neutral polarizer mentioned in Example 1 with parallel directions of the plane of vibration and orientation of the stretched polyvinyl alcohol it appeared blue. When the polarizer was rotated by 90 °, the blue turned into green and finally became light golden yellow. When the color stripe was viewed with the two-field polarizer from Example 1, the result the upper part was blue and was in excellent sharp contrast to the lower part, which appeared yellow.

Example 3

The measures of Examples 1 and 2 were repeated using the following dye liquor: 37.5 g of acid dye "Yellow 152" as a negative dichroic dye and 2.5 g of "Direct red 117" as positive dichroic dye, dissolved in 500 ecm water and 100 ecm ethanol. The streak appeared orange with the naked eye, red with the neutral polarizer in parallel alignment and at 90 ° C rotation of the polarizer after changing color to orange and finally yellow. By doing Two-field polarizer, the upper part appeared red again and stood in sharp contrast to the lower part Part that appeared yellow.

Claims (2)

Patent claims: 1. Forgery-proof image and writing-bearing surfaces with at least one light-polarizing surface Coating based on molecularly oriented polymers, especially polyvinyl alcohol, characterized in that the coating has one or more dye strips or -areas and the dye strip or areas either two opposite dichroic dyes or an isotropic dye together with a dichroic dye Contains dye of different colors. 2. Counterfeit-proof surfaces according to claim 1, characterized in that the coating on Replace two oppositely dichroic dyes with a double dichroic dye contains. 1 sheet of drawings