DE4338218C2 - Process for producing a hologram or diffraction grating and hologram or diffraction grating produced according to it - Google Patents

Description

The invention relates to a method for producing a Halograms or diffraction gratings and one according to this procedure ren manufactured hologram or diffraction grating.

Holograms are now widely used Experienced. Individual, different sized transmission or Reflection holograms are not just objects of art and get pictures. Virtually all check cards will be today to increase the security against counterfeiting with the be matching financial institution or the issuer of the check card identifying holograms.

The production of corresponding holograms is up to today, however, still very complex and above all  expensive. This applies equally to transmission as also reflection holograms or, for example wise for the so-called "rainbow holograms" in print process are manufactured and for example on the Title page of books or magazines attached the.

In all of these procedures, a laser is used first a picture of a hologram is made. This requires a substantial, even costly precipitating expenditure on equipment. Furthermore Such holograms can usually only be obtained through a specialist people are accepted.

After the inclusion and development of such a first The master or master hologram can also do this that using lasers in different ways be copied.

A master hologram is thereby usually knocked out piert that the image stored in the master hologram clears Lich reconstructed and using the mentioned Lasers in the by a sharp image reproduction a light-sensitive material and is additionally exposed with a reference beam. Here the so-called photoresist is often used for the interference pattern applied as a surface relief becomes. The photoresist hologram thus developed is then metallized, then in a subsequent gal vanoplastic process step, for example Coating, d. H. Evaporation with a silver and / or Nickel layer a corresponding negative impression of the Obtain hologram as a mother matrix. By more Multiple copies can be a positive or negative stamp be generated.  

Is the hologram so produced still comparatively small, for example, has an order of magnitude of only one or more cm, so mostly Ko multiple copies of the same hologram image manufactured and combined into a common printing plate added to the same in a printing or manufacturing process to be able to produce 50 holograms, for example as they u. a. also integrated into check cards Identification of the issuing institute can be used.

Apart from the different hologram images there are of course also simple diffraction grating phenomena and -Images, by means of which also a spatial image or to at least interesting light refractions, e.g. B. in the below different rainbow colors can be created.

Because of the extremely complex process and the associated high costs are the conventional, above described methods for generating a hologram economically justifiable only if correspondingly high Numbers of at least 500,000 copies, for example Plaren are manufactured.  

A method for producing a hologram is in the became known for example from CH 530 018. To the Improving the resolution of a hologram is according to the ser pre-publication proposed, the carrier material for the hologram forming film tape between one let the upper and lower calender roll pass through. The film to be minted then runs over the same one Speed moving hologram film matrix that the Has the form of an endless band and this on the film has relief patterns to be embossed. The die will be there supported by support and deflection rollers. To get a better one To achieve resolution, the embossing temperature becomes significant below the flow or softening temperature of the thermo plastic copying material.

According to CH 604 215 is a method for generating a Surface relief image became known, which just if produced by pressing and embossing. This before Publication is based on the task of a procedure to develop that makes it possible to use an electroma electromagnetic radiation with low energy consumption on one Image carrier made of thermoplastic material a surface to create a relief image. This is done in that by a pressing or embossing process in the image carrier elastic tension field is entered, which by Wär me action is deformable in a relief structure, and that the surface relief image corresponding to the image shape The effect of heat on the image carrier is recorded.

According to DE 37 44 650 A1 is a holographic embossing described method in which a pre-compressed coated printing material is used, on one Lacquer layer is applied, through which the hologram a metallization is stamped through. By on Pressing an embossing stamp becomes the final hologram  manufactured. Due to the specific meaning of one thermoplastic deformable lacquer layer applied, light-reflecting metallization is said to be the advantage aims to avoid embossing on a separate carrier must be done, but that printing on a substrate fes is made possible directly.

Just in case there are others besides the holograms light diffractive structures and so-called diffraction gratings or Diffraction patterns can also be desired be impressed.

According to DE 27 01 176 B1, a method for creating described a document in which an authenticity hiding information in a way that was previously unknown and which one can be faked only with great effort that can.

This document has an information carrier in which an elastic stress field is entered. This span field can be even over the entire surface or over a partial area of the information carrier stretch, it also in a variety of separate A fields can be divided. By the information sluggish or a partial area of a radiation effect or exposure to heat the elastic stress field in the relevant area transformed into a relief structure. The elastic chip This is preferably achieved by an embossing process entered in the information carrier. Furthermore, can in the information carrier one of the relief structure ver various other relief structures are embossed, the is superimposed on the first relief structure.

According to DE 26 57 246 C2, a method for manufacturing len of an original of an information carrier  ben into which a relief image containing the information is embossed, the relief image consisting of several Relief sub-images adjoining each other without overlap composed, which a relief grid with differ Chen grid depths in the areas of each Relief drawing files are superimposed.

In this respect, it is only an addition of several rer different hologram images (the usual Process produced) to an overall picture.

In contrast, it is an object of the present invention to create a much simpler process by which Holograms or diffraction gratings at least for generation simple virtual effects and image structures with ver can be produced with equally little effort, and above all even at comparatively low ones Quantities.

The task is carried out according to the procedure in claim 1 and with respect to the Holo produced thereafter Gram or diffraction grating with respect to that in claim 11 specified features solved. Advantageous configurations the invention are specified in the subclaims.  

The present invention makes a completely new one Tread the path. It is proposed for the first time by means of of a comparatively small stamp, the only a partial area that may be small of the final hologram or diffraction grit ters has a final hologram or diffraction grid in its total size in several advanced to manufacture. In other words, such "Tool" in the form of a stamp step by step by embossing another, the stamp impression speaking diffraction grating on the carrier material first the final hologram or diffraction grating in its Overall size and shape made.

According to the invention, the stamp itself, i. H. the Stamp area prepared and prepared accordingly in advance tet. As a rule, the desired diffraction grit is used ter structure on the stamp surface in the usual process manufactured in the same way as conventional holograms be put. But different so-called Hologram stamps are formed, for example with a diffraction grating structure that is later used in this finally made hologram or the diffraction grating Er apparently a red, yellow, green or blue color generated. The lattice structures can be chosen in this way be that the various, just example above color effects mentioned in different Layers lie to each other.

According to the chosen diffraction pattern you can use different pictures through the explained individual steps getting produced. These images can have certain colors effects, light refraction effects or rainbow effects point. You can also use "Tie effect "if a stamp with a corresponding diffraction grating or several stamps with under  different diffraction gratings are used or com men. This allows z. B. so-called 2D or 2D / 3D images produce. In the former case it is about "flat" images, reflections, image or in particular Color effects. In the latter case, the ge suitable lattice structure the reflections or color re- appeared in "staggered" levels NEN, which creates the flat color or reflection appearances due to the different, in the plane offset "depth effect" the so-called "3D" effect surrender.

So to get more complex holograms or diffraction gratings testify, it is finally in a continuing education course Invention also possible that, for example, differ che stamps are used, with which only one certain partial area or the entire area on the Material carrier is processed superimposed. Through the he mentioned hologram stamps or the several differences hologram stamp can not only be a complex 2D / 2D, a 2D / 3D hologram or diffraction grating phenomenon, but also a more complex final overall hologram are generated, in which, for example, a 3D / 2D or 3D / 3D part hologram is embedded, which is common Technology is made. That is, such in the usual Technically produced hologram is embedded in one larger produced with the inventive method Hologram or diffraction grating image.

With this method, a corresponding one can preferably be used Plastic material, for example PVC material or a PVC film used to produce high light reflection even with silver or other suitable, high light reflective materials can be coated, to be edited.  

The embossing pressure of the stamp must be sufficiently high.

The embossing process is also preferred using Warmth supports or relieves.

In a particularly preferred embodiment in this case particularly suitable for ultrasonic welding devices. With them, the area of the stamp surface can be targeted heated to a desired temperature and thus the Transfer and embossing process on the stamp surface structure, i.e. the Beu located on it grid, on the material to be treated accordingly al, usually through the plastic material easily be performed.

The invention is described below with reference to drawings explained in more detail. Show in the individual:

Figure 1 is a schematic enlarged bottom view of a stamp surface with incorporated diffraction grating (hologram).

Fig. 2 is a schematic outline illustration to illustrate a Beu supply grating to be produced with areas shown therein, in which an engraving or embossing of the lattice structure formed on the stamp surface is carried out on the carrier material;

Fig. 3 is a schematic side view of an on device for producing a hologram or diffraction grating, in particular in the form of an ultrasonic welding device.

In Fig. 3 is a schematic side view of an on device 1 for producing a final hologram or diffraction grating on a suitable carrier material is shown. The device 1 in FIG. 3 is a so-called welding device, namely an ultrasonic welding device, as is usually also used for welding plastic materials, in particular plastic films.

Such devices usually work with an inte grilled transducer, which is centrally located in a cylinder is built, which is not only a small size results, but also an optimal force and temperature transfer is guaranteed on the welded part. Here can use different metal welding sonotrodes become.

The device 1 includes the shown in Fig. 1 and axially movable in height 3 punch, which is lowered during the machining process down to a worktop 5 , on which the processing and in Fig. 3 in cross-section film-like Träger material 7 is located. This is usually a PVC support which is coated with silver, on which the individual processing steps to be explained below are then carried out.

In Fig. 2, the stamp surface 11 is shown in an enlarged bottom view. This stamp surface 11 has a diffraction grating previously introduced by suitable mechanical, chemical and / or optical methods. It is usually a hologram produced according to the conventional method, a diffraction grating etc., of which a mother matrix (master) was produced and then attached to the lower surface of the stamp.

In Fig. 1, the size of a diffraction grating or Holo 8 to be produced , for example, is shown in a schematic plan view. The mentioned carrier material 7 is thus placed on the worktop 5 and the stamp 3 is moved down onto the carrier material and pressed onto the material while generating heat, so that the diffraction grating structure located on the stamp surface 11 is impressed in the carrier material 7 . Due to the targeted heat generation, the plastic is made softer and more flowable, which not only makes the embossing process easier and faster, but also, above all, ensures optimal transmission and reproduction of the diffraction grating structure formed on the stamp surface 11 in negative form on the carrier material 7 can.

Through the subsequent process of the carrier material 7 in relation to the coordinate position of the stamp surface 11 , an impression 10 after the other is then placed next to one another on the carrier material 7 by successively impressing the stamp surface 11 , as is shown schematically with reference to FIG. 1. In this example, a large number of impressions 10 of the stamp surface 11 lying next to one another have been impressed into the carrier material 7 . The remaining area of the overall picture giving frame 13 results when the entire surface is machined accordingly.

By a suitable pre-selection and manufacture of the diffraction grating structure located on the stamp surface 11 , a very specific hologram or diffraction grating can be produced in several individual successive steps. The diffraction grating embossed on the carrier material 7 can only bring about color and light refraction effects. However, you can also generate spatially structured images if an appropriately suitable diffraction grating incorporated on the stamp surface 11 is used.

For example, hologram stamps can preferably be used which have a diffraction grating structure which produces color reflections in red, yellow, green or, for example, blue on the carrier material. In this case, a diffraction grating structure can be selected which generates the different color reflections mentioned above in a different reflection plane. In other words, if the impressions 10 are produced with different stamps in FIG. 1, then after a predetermined, u. U. computer-controlled methods certain different coloring effects are generated at different points on the final hologram 8 to be produced with, for example, different depth effects resulting in a 3D effect. As a result, a large number of individual embossing steps can produce a so-called 2D / 3D image that is dimensioned large compared to the stamp surface, ie stamp size, which reproduce a spatial 3D effect due to the different color reflections and the reflection planes generated differently for the individual color reflections .

In the embodiment according to FIGS. 1 and 2 where a hologram or diffraction grating stamp has been used 11 having a rectangular, preferably square in shape. As a result, a full-surface end hologram or diffraction grating 8 can be produced on the carrier material 7 . The stamp can also have different shapes, for example a circular shape. In this case, the individual impressions on the carrier material 7 would also be made lying side by side, the individual stamp impressions 10 not overlapping. The remaining unprocessed th surface sections between the individual circular stamp impressions 10 are of no significance, since the area of the stamp 11 or the empty spaces without impressions between the individual circular impressions is negligibly small compared to the size of the final hologram.

In addition, an overlapping impression can also be made made at the successive advanced become. In many areas, these do not lead to any problems pregnancy. Depending on the point of view, overlapping area even different lighting effects generated in the same place.

The different impressions 10 can be made computer-controlled in such a way that, for example, in the case of a complex hologram or diffraction grating 8 to be finally manufactured, first of all by means of a first hologram stamp 11 in the end hologram or end diffraction grating 8 to be generated, those positions or "pixels -Faces " 10 are impressed, which ter should produce a" red "image effect in the final hologram or diffraction grating, that is to say, for example, a red light reflection at certain viewing angles and light incidence angles. Then, with a next hologram stamp 11, all those parts of the image are embossed on the carrier material 7, which, for example, cause "yellow" light reflections at a certain light incidence and viewing angle. In a third and / or fourth method step, for example, those locations on the carrier material 7 can then be processed, ie corresponding stamp impressions 10 can be introduced, which are intended to cause “green” or “blue” light reflections. However, several stamp impressions 10 can still be used, with which the same color reflections as, for example, red, yellow, green or blue are produced, but on a different, offset spatial plane. This means that different spatial 3D effects can be achieved.

The stamp area can be of any size. Each however, the smaller the area, the higher the resolution solution. Stamp areas with a size of <10 mm², ins particular <5 mm² or even <1 mm² are preferred related. For example, he can achieve good results aim when the stamp area has a value of about 1/10 up to 5/10 mm², i.e. less than 1 mm².

It is essential that holograms of any size are used can be produced on the carrier material, problem go for example up to A4 size or even larger, the hologram generation fully automatically computerge controls can run.

Claims (11)

1. A method for producing a hologram or diffraction grating on a carrier material ( 7 ) by means of a stamp, the surface structure of which is embossed in the carrier material ( 3 ) to be processed, characterized in that a stamp ( 3 ) is used, the stamp surface ( 11 ) based on the hologram or diffraction grating to be finally produced, only represents a partial area, the total size of the final hologram or diffraction grating using the at least one stamp ( 3 ) in a plurality of successive mechanical advances by embossing a further diffraction grit corresponding to the stamp impression ters is produced on the carrier material. 2. The method according to claim 1, characterized in that a polygonal shape, preferably a rectangular and in particular square shape is used for the stamp surface ( 11 ) with the diffraction grating located thereon in plan view. 3. The method according to claim 1, characterized in that a curvilinear shape, in particular elliptical to circular shape, is used for the stamp surface ( 11 ) with the diffraction grating thereon in plan view. 4. The method according to any one of claims 1 to 3, characterized in that the successive mechanical embossing steps by means of the stamp ( 3 ) while increasing the temperature of the carrier material ( 7 ). 5. The method according to any one of claims 1 to 4, characterized in that the stamping force of the stamp ( 3 ) on the carrier material ( 7 ) and the temperature increase is carried out by means of a plastic welding device, preferably by means of an ultrasonic welding device. 6. The method according to any one of claims 1 to 5, characterized in that at least two different partial holograms or partial diffraction gratings are used on at least two different stamps ( 3 ) or stamp surfaces ( 11 ). 7. The method according to any one of claims 1 to 6, characterized in that several hologram or diffraction grating ter stamp ( 3 ) with different diffraction grating structures having stamp surfaces ( 11 ) are used with which different color reflections and / or un Different reflection levels can be generated on the carrier material ( 10 ) when the hologram or diffraction grating ( 8 ) to be finally manufactured is considered. 8. The method according to any one of claims 1 to 7, characterized in that different stamp attachments ( 3 ') are interchangeably mounted on the print underside of the stamp ( 3 ). 9. The method according to any one of claims 1 to 8, characterized in that stamps ( 3 ) are used with a stamp surface having a size <10 mm², in particular <5 mm², preferably <1 mm². 10. The method according to claim 9, characterized in that stamps ( 3 ) are used with a stamp surface whose size is smaller than 1 mm² and preferably have an area of 1/10 to 5/10 mm². 11. hologram or diffraction grating, produced on a carrier material ( 7 ), by means of a stamp ( 3 ), the surface structure of which is embossed into the carrier material ( 3 ) to be processed, for which purpose a stamp ( 3 ) is used, the stamp surface ( 11 ) of which the final hologram or diffraction grating to be produced only represents a partial area, the total size of the final hologram or diffraction grating using the at least one stamp ( 3 ) in a plurality of successive mechanical advances by embossing in each case a further diffraction grating corresponding to the stamp impression Carrier material is generated.