DE20023780U1 - Packaging tape, used for storing holographic information e.g. by local heating or exposure to light, has a polymer film as the holographic data carrier - Google Patents

Abstract

packing tape for use as a holographic data carrier, wherein the packing tape (3; 3 ') has a polymer film (12; 32; 52) and for storing holographic Information is set up.

Description

The The invention relates to a packaging tape comprising a polymeric film and as a holographic disk can be used.

Packaging tapes, the a polymer film whose underside usually with a Adhesive layer is provided when packaging objects in great Scope used. Often the polymer film is reinforced by a fabric insert. One such packing tape may e.g. to be wrapped around a cardboard box, to close the carton and if necessary, also to seal or reinforce.

For logistic Purposes are currently in addition to conventional Transport papers mainly used barcodes. In doing so, e.g. a label with a one-dimensional or two-dimensional barcode glued on a package. The barcode contains e.g. a reference number, the with the help of electronic data processing more information can be assigned. The direct storage capacity Barcodes are very limited. In the near future is also with the use of transponders for logistical purposes. Transponders have the advantage that they can be detected without free optical vision. Your storage capacity on the other hand, it is low and the cost of a mass deployment is currently still too.

It Object of the invention, a simple and inexpensive way to create an object, especially a wrapped object or its packaging, with a larger amount of information to provide.

These Task is solved by a packaging tape with the features of claim 1. Advantageous Embodiments of the invention will become apparent from the dependent claims.

According to the invention is a Packing tape having a polymer film applied as holographic data carrier, the packing tape for storing holographic information is set up. Preferably, the packaging tape for packaging objects used. Other applications, e.g. as a label, but are as well conceivable. In a preferred embodiment, the packing tape Apply an adhesive layer to make it self-adhesive to an object adheres. It may also have other components, e.g. a fabric insert as Gain.

There set up the packing tape for storing holographic information is, it can be big Record data volumes. Unlike traditional barcodes, therefore an item in a direct way larger amounts of information be assigned. Examples of this are in a package that is packaged using the packaging tape is, the delivery address, the sender, transport documents, as well e.g. Safety data sheets, manuals and the like. So allows it the invention, objects on fast and cost effective Ways to pack and save with less work involved information for logistical purposes, but also to provide additional information.

The Holographic information is preferably in the form of machine-readable Data pages stored, as explained in more detail below. When using the Packbands can be a first Be packaged using the packaging tape, and then holographic information entered into the packaging tape. alternative can first holographic information is entered into the packaging tape, e.g. after unwinding from a supply roll in one for that purpose provided writing device, and then the subject is under Use of the packaging tape packed. Mixed forms are also conceivable where holographic information before and after packaging of the item is written in the packing tape. In such Applications can be conventional Use packaging machines. Only for entering the holographic Information is an additional writing device required. Such writing devices, e.g. a laser lithograph have a relatively small volume, leaving an existing one Packaging machine be retrofitted with reasonable effort can. The information to be entered in the packaging tape can be without problems specific to the given object to be packaged vote.

suitable Materials for the polymer film are e.g. Polypropylene, polyvinyl chloride, polyester, polyethylene terephthalate (PET), polyethylene naphthalate, polymethylpentene (PMP; also poly-2-methylpentene) as well as polyimide. The polymer film preferably has a starch, such as they at conventional Packing tapes is common and for the desired Strength required. if only a limited number of areas of the packaging tape for storing holographic information is (see below), can Such areas have their own polymer film that significantly thinner is considered the supporting structure of the packaging tape; in this case it is too conceivable that the support structure of the packaging tape itself no polymer film having.

The polymeric film may be stretched and is preferably biaxially stretched, eg by being pre-formed within its plane in two mutually perpendicular directions during manufacture is tense. This usually increases the strength of the polymer film. Furthermore, a high energy density is stored in a stretched polymer film in the film material. By local heating with deposition of a relatively small amount of energy per unit area, for example by means of a writing beam of a writing device, a relatively strong change in material can be achieved with a change in the local properties of the polymer film.

stretched Polymer films are therefore particularly suitable for an advantageous embodiment the invention. The polymer film is locally changeable by heating and for storing holographic information about the established local properties of the polymer film. There are different possibilities to take advantage of this effect.

at a possibility the refractive index of the polymer film is locally variable by heating, wherein optical phase information about the local optical path length is stored in the polymer film and it is provided, the Transmitting polymer film when reading information in transmission. In the polymer film leaves So locally, d. H. in a space provided for storing an information unit Area, provide phase information by using the Refractive index by heating (e.g., by means of a writing beam of a writing device). The local change the refractive index causes a change the optical path length used in reading out information from the polymer film Radiation (which transmits the polymer film in transmission). The optical path length is that the product of the geometric path length and the refractive index; about a change the refractive index leaves So the local phase of the reading of information used radiation, i. the desired holographic Save information as phase information. One in this way Accordingly, in the polymer film of the packaging tape produced hologram is a refractive phase hologram.

at another possibility is the surface texture the polymer film can be changed locally by heating, where holographic information about the local surface structure the polymer film is storable. In this case can be So the surface structure or localize the topography of the polyer film, e.g. as a writing beam Serving laser beam on the polymer film, preferably the surface zone, is focused so that the light energy is absorbed there and in Heat energy converted becomes. In particular, when the laser beam briefly (pulsed) irradiated will, that remains to the local change the surface structure premier material change in the polymer film due to the generally poor thermal conductivity of the Poylmers limited to a very tight volume. If the holographic Information point for Point is entered into the polymer film of the packaging tape, wherein the A region associated with a point is typically linear lateral Dimensions in the order of magnitude of 0.5 μm up to 1 μm has, changes the height profile the polymer film typically by 50 nm to 500 nm, which in detail of the characteristics and operating conditions of the writing beam and the properties of the packaging tape. The dot screen, i. the center distance between two points ("pits"), is typically in the range of 1 micron to 2 microns. In general, shorter light wavelengths of the Write beam allow a narrower dot pattern.

Of the Polymer film may be associated with an absorber dye, which is arranged, serving for inputting information write beam at least partially to absorb and the heat generated at least partially deliver locally to the polymer film. Such an absorber dye allows a to change the local properties of the polymer film (e.g., the change the local refractive index or the local surface structure) sufficient local warming the polymer film at relatively low intensity of the writing beam. The absorber dye may be contained in the material of the polymer film. He can but also be arranged in a separate absorber layer, preferably a binder; Mixed forms are also conceivable. So For example, the absorber layer may be e.g. a thin layer (e.g., a thickness of 0.5 μm up to 5 μm) of an optically transparent polymer (e.g., polymethyl methacrylate (PMMA) or, in applications for higher Temperatures, of polymethylpentene, polyetheretherketone (PEEK) or Polyetherimide), which acts as a matrix or binder for the molecules of the absorber dye serves. The absorption maximum of the absorber dye should with the wavelength of light of the used write beam coincide to an efficient To achieve absorption. For a wavelength of light of 532 nm of a laser generated write beam are e.g. Dyes from the sudanrot family (diazo dyes) or (for especially polar plastics) Eosin scarlet suitable. For the common laser diodes with a Light wavelength from 650 to 660 nm or 685 nm are green dyes, e.g. from the Styryl family (which are commonly used as laser dyes), more suitable.

In an alternative embodiment, the polymer film carries a dye layer with an alterable by exposure dye. In this case, the holographic information on the local absorption capacity in the dye layer is storable. When information is read out, the dye layer is irradiated, whereby the locally varying absorptivity as a result of changes in the dye ability in the dye layer affects the radiation, which allows the reconstruction of a holographic image. The local area for storing an information unit typically has linear dimensions (ie, for example, a side length or a diameter) on the order of 0.5 μm to 1 μm, but other sizes are possible.

Preferably become the molecules of the dye upon exposure to radiation used to enter holographic information is used, bleached or destroyed. By "fading" is meant the damage the chromophore system of a dye molecule by excitation with intense Light of suitable wavelength, without doing the skeleton of the dye molecule to destroy. The dye molecule loses its color properties and is at sufficient Exposure for the light used for bleaching optically transparent. Will against it also the basic framework a dye molecule destroyed, One speaks at the change caused by the exposure from "destruction" of the dye. The used for exposing, that is, for entering information Light does not have to be in the visible wavelength range.

The Dye layer preferably has a polymer matrix into which dye molecules are embedded. Preferably, the dye molecules are homogeneous distributed in the dye layer or part of the dye layer. As materials for the polymer matrix can offer polymers or copolymers, e.g. Polymethyl methacrylate (PMMA), polyimides, polyetherimides, polymethylpentene, Polycarbonate, cycloolefinic copolymers or polyetheretherketone (PEEK), at. When making the tape, a polymer matrix, the dye contains e.g. by knife coating on the serving as a carrier polymer film or on a previously applied to the polymer film reflection layer (see below) are applied.

When Dye are easily bleachable dyes particularly suitable such as. Azo and diazo dyes (e.g., the Sudan Red family). That's how it works Sudan Red family dyes Information with a writing beam a wavelength of light of 532 nm. Preferably, however, such dyes are not so unstable to exposure that already duch ambient light (Sun, artificial Illumination) begins a bleaching process. If the writing beam With a laser, significantly higher intensities can be achieved Dye layer than when exposed to ambient light, allowing dyes to be available stand for the desired Application at least largely insensitive to ambient light are. The dye does not have to be sensitive to light, completely unlike a photographic film. Should the dye not bleached, but destroyed with higher laser power, you can rely on a variety of dyes. Preferably while the absorption maximum of the respective dye to the wavelength of adapted as a writing beam used laser. Other suitable Dyes are polymethine dyes, arylmethine dyes, aza [18] annulene dyes and triphenylmethane dyes.

There it possible should be, the holograms of the packaging tape, i. the in the packing tape input holographic information, even if read the packing tape e.g. glued on a package, it is advantageous when the packaging tape has a reflective layer adapted thereto is, for reading holographic information serving light to reflect. The light is directed to the packaging tape and reflected from the reflective layer, being excluded from the for storing holographic information caused changes is modulated on the packing belt. The reflected light can then in a favorable geometric arrangement captured to a holographic image to reconstruct the holographic information. At which point of the packaging tape, based on its cross section, the reflection layer on most advantageous, depends on the effect, the is used for storing holographic information. Of the Reading process can also be done without additional reflective layer, which Depending on the application, it can even lead to better results.

If optical phase information about the local optical path length is stored in the polymer film, it is provided, the polymer film in the Readout of information, preferably in transmission. In this case, the reflection layer is preferably between the polymer film and an adhesive layer. When holographic information about the local surface structure the polymer film is stored, the reflective layer also be disposed between the polymer film and an adhesive layer; in this case, the surface texture becomes the polymer film radiates twice during the reading out of information. Alternatively, the reflective layer on the surface of the Polymer film may be arranged, their local structure when entering the holographic information is changed, so preferably the top of the polymer film. When a dye layer is used comes, which radiates when reading information in transmission when the reflection layer is e.g. between the polymer film and the dye layer or between an adhesive layer and the Polymer film.

The holographic information to be stored can be entered into the packaging tape by ent in a hologram memory object a holographic information is calculated as a two-dimensional array and a writing beam of a writing device, preferably a laser lithograph, directed onto the packaging tape and driven in accordance with the two-dimensional arrangement so that the local properties of the packaging tape are adjusted according to the holographic information. For example, since the physical processes in scattering light on a memory object are known, a conventional structure for generating a hologram (in which coherent light from a laser scattered by an object (memory object) is made to interfere with a coherent reference beam and the resulting interference pattern is recorded as a hologram) is simulated using a computer program and the interference pattern or the modulation of the local properties of the packaging tape are calculated as a two-dimensional array (two-dimensional array).

As already explained above, are examples of the local properties of the packaging tape, according to the holographic information be adjusted, the local refractive index of the polymer film, the local surface structure the polymer film and the local absorption capacity of a supported by the polymer film dye layer.

The resolution a suitable laser lithograph is typically about 50,000 dpi (dots per inch). Thus, the polymer film or one of the Polymer film-borne dye layer locally in areas or Pits a size of about Be changed 0.5 microns to 1 micron. The writing speed and other details depend, among other things, on the parameters of the write laser (laser power, wavelength of light) and the exposure time as well as the properties of the polymer film, the dye layer or any absorber dye.

The Holographic information is thus preferably in the form of pits entered given size; the term "pit" is more general here in the sense of an altered one Area to understand and not limited to its original Meaning (hole or depression). It can be in a pit the holographic Information in binary encoded form. That is, in the range of a given Pits take the local properties of the packaging tape only one of two possible basic forms (Basic values). These basic forms preferably differ clearly, so that in practice occurring intermediate forms, close to one or the other basic form, clearly the one or the other basic form can be assigned to the information reliably and to save clearly.

alternative can in a pit the holographic information in continuously encoded form, the local characteristics of the Packbands in the pit according to a Value can be set from a predetermined range of values. If e.g. the local surface structure the polymer film is to be adjusted, so is the local maximum altitude change the surface structure in the pit selected from a predetermined range of values. This means that in a given pit the surface structure of the polymer film Intermediate forms between two basic forms can assume, so that the maximum height change the present intermediate form a value from a given Value range assumes its limits by the maximum height changes given the two basic forms. In this case can be the information is "in Grayscale ", so that each pit has the information content of more than one bit due. The same applies to the Adjustment of the local refractive index of the polymer film or the local absorptivity in the dye layer.

To the Reading holographic information from the packaging tape can light, preferably coherent Light (e.g., from a laser), directed over the packaging tape over a large area become. At the same time the light becomes of the locally varying properties of the packaging tape (e.g., refractive index or surface texture) the polymer film or the absorptivity of the dye layer). After reflection on the packaging tape, so preferably after reflection at a reflection layer, is used as a reconstruction of the in the holographic information contained in the light-detected area captures a holographic image at a distance to the packaging tape, e.g. with a CCD sensor connected to a data processing device connected is.

The term "large area" means an area that is significantly larger than the area of a pit. In this sense, for example, an area of 1 mm ^{2 is} large. There are many different possibilities for the scheme according to which information is stored and read out. It is conceivable to read out a hologram on the packing tape at once by irradiating the entire surface of the hologram-mounted portion of the packing tape at once. However, especially with larger areas, it is advantageous to divide the information to be stored in a number or plurality of individual areas (eg with a respective area of 1 mm ² ) and to read the information only from a given single area at a time.

When information is read out, the locally varying properties of the packaging tape lead to differences in transit-time of the light waves emitted by different points, that is, essentially to a periodic phase modulation (This applies in particular to a local adjustment of the refractive index or the surface structure of the polymer film) or to an amplitude modulation (in particular in the case of a locally varying absorption capacity of a dye layer). The area of the tape caught by the light acts like a diffraction grating which deflects incident light in a defined manner. The deflected light forms an image of the memory object that represents the reconstruction of stored holographic information.

Basically you can with the packaging tape holographic information of different types use of storage objects. Thus, e.g. in pictures, e.g. Photographs, logos, writings, etc., contained information stored and read out. However, saving is particularly advantageous machine-readable data, since e.g. the data mentioned at the beginning, such as delivery address, sender, transport documents, safety data sheets, manuals and the like, can be stored. This takes place for example in the form of so-called data pages, wherein in a hologram of a graphic bit pattern (representing the data information) contained holographic information as explained in the packaging tape entered becomes. When reading a holographic image of this graphic arises Bit pattern. The information contained therein may e.g. with help a precisely adjusted CCD sensor detected and processed by associated evaluation software become. For the reproduction of images that are not at high accuracy arrives, in principle already enough a simple screen or e.g. a camera with an LCD screen. At the holographic Storage of machine-readable data, it is advantageous that the Information does not have to be read sequentially, but that a whole record can be captured at once, as explained. Should the surface of the packaging tape damaged be so leads this in contrast to a conventional one Datastore not to a data loss, but only too a deterioration of the resolution the holographic image reconstructed upon reading the information, which is usually unproblematic.

It It is not necessary for the entire packing tape to be stored is furnished by holographic information. For the explained Purposes, it is usually sufficient if the packing tape only one Number of limited areas, each for storing holographic Information is set up. With such an embodiment let in some circumstances Save costs, because it can be a conventional, cost-effective Packing tape can be used as a starting material only in the limited Areas more elaborate to the writing and reading of holographic information. Such limited For example, areas can be created by using an absorber dye by means of a printing process on a packing tape from stretched Polypropylene, polyvinyl chloride or polyester film applied becomes.

It It is also conceivable that the limited areas each have their own Piece of polymer film have, optionally on the additional layers such as a Absorber layer, a dye layer or a reflective layer are applied to the storage of holographic information for example, according to one of the possibilities explained above. so designed limited areas may affect the support structure of the Packbands (which may or may not have a polymer film) e.g. glued or welded on. However, it is preferred to provide as polymer film a common polymer film for the entire packaging tape, For example, a polymer film that simultaneously supports the supporting structure of the Packing tape represents. On this polymer film can then be e.g. by applying said additional layers only in the limited Provide areas of zones where the possibility of storing holographic Information is given.

Preferably are the limited areas at predetermined intervals arranged the packing tape. This facilitates the input and readout holographic information in automated systems. The limited areas can for example, circular with a diameter of 6 mm and mutual center distances in the longitudinal direction of the packing tape of 40 mm.

If holographic information is deleted from the packaging tape again should, the holograms concerned preferably with a strong Write beam destroyed. In this case, the destroyed one stands Area no longer for storing new information is available, which, however, is usually irrelevant, because of the large storage density, the holograms offer, mostly still unused zones on the packing tape are present, in the holographic information can be entered.

in the Below, the invention will be explained with reference to embodiments. The Drawings show in

1 12 is a schematic diagram illustrating how holographic information is written to a packing tape before the packing tape is glued around a package,

2 12 is a schematic diagram illustrating how holographic information is input to a packaging tape already glued around a package,

3 FIG. 2 is a schematic plan view of a detail of a region of the packaging tape configured to store holographic information, FIG.

4 3 shows a schematic longitudinal section through a region of the packaging band which is provided for storing holographic information and in which holographic information about the local optical path length can be stored in a polymer film,

5 a longitudinal section according to 4 wherein the processes of reading out information are illustrated schematically,

6 a schematic longitudinal section through an established for storing holographic information area of the packaging tape, in which holographic information on the local surface structure of a polymer film is stored, wherein with the aid of a write beam information is entered,

7 a longitudinal section according to 6 after the surface structure has been locally changed to input the information,

8th a longitudinal section according to 7 wherein the processes of reading out information are illustrated schematically,

9 a schematic longitudinal section through an established for the storage of holographic information area of the packaging tape, in which holographic information about the local absorption capacity is stored in a dye layer, and

10 a longitudinal section according to 9 , where the operations of reading out information are schematically illustrated.

In the 1 and 2 Fig. 12 schematically illustrates how a package is packaged using a packaging tape and holographic information is entered into the packaging tape serving as a holographic data carrier. This information can be provided for logistical purposes and include, for example, the delivery address and the sender as well as the transport documents for the package. Since holographic data carriers have a high storage capacity, in principle also other data in the form of holograms can be stored on the packaging tape. Examples include safety data sheets, manuals and the like, ie data related to the content of the package. In addition, other data content can be stored in holographic form on the packaging tape.

In 1 will be a package 1 on a treadmill 2 transported. A packing tape 3 ("Carton Sealing Tape", CST) is over the treadmill 2 and introduced counter to its direction by means of a conventional packaging device. The packing tape 3 is configured to store holographic information, as further explained below. Above the packing tape 3 there is a writing device 4 using a laser beam as a writing beam 5 used holographic information in the packing tape 3 enter. In the embodiment, the writing device 4 a laser lithograph. Subsequently, the packing belt passes through 3 guide rollers 6 and will be on the package 1 applied.

The packing tape 3 is provided on its underside with an adhesive layer, so it attaches to the package 1 that in the embodiment has a cardboard packaging adheres and the package 1 closes and seals. These steps are performed on a conventional plant. New is added only the writing device 4 , which due to its relatively small size can easily be installed on an existing system.

2 shows a variant of the procedure. This is a package 1' on a treadmill 2 ' emotional. The package 1' is already with a packing tape 3 ' locked. Above the package 1' (ie at a point under which the package 1' moved through) is a writing device 4 ' with a writing beam 5 ' arranged, which is preferably designed as a laser lithograph. Here, the holographic information is in the packaging tape 3 ' entered after the in the package 1' subject using the packaging tape 3 ' has been packed.

It is also conceivable to include a part of the holographic information in the packaging tape 3 respectively. 3 ' register before it on the package 1 respectively. 1' and a part of the holographic information afterwards.

In the exemplary embodiment, the packing tape 3 respectively. 3 ' a polymer film having a thickness of 35 μm made of biaxially oriented polypropylene. At the bottom of the polymer film is the adhesive layer, which is 20 microns thick and consists of functionalized poly (meth) acrylate. The holographic information is stored in the exemplary embodiment according to FIG 9 and 10 explained method, wherein the top of the entire tape is set up to store holographic information. Therefore, a semitransparent reflective layer of aluminum (about 10 to 20 nm thick) is applied to the top of the polymer film, and over it are a dye layer and a protective layer.

The packing tape can also use other materials or have dimensions or additional components, eg a reinforcing fabric insert. Such a fabric insert is preferably arranged below a polymer layer and may also be embedded in additional polymer. Other components of the packaging tape are any components required to store holographic information (see below).

at other embodiments the packaging tape only limited areas are provided, the at predetermined intervals arranged to each other and each for storing holographic Information is set up while the packing tape in the intermediate zones as a simple packing tape without the possibility designed for holographic data storage. Such limited Areas can e.g. each have a diameter of 5 mm and distances of 50 mm to each other. You can for example, one piece each Have polymer film, one of the embodiments described below have and on a conventional one Packing tape glued or welded.

in the Following are different options for storing holographic information by means of a tape using examples explained.

3 Fig. 10 is a schematic plan view of a portion of an area arranged to store holographic information 11 a packaging tape into which information is entered. In the embodiment, the area 11 (hereinafter referred to as "storage area") has a limited area with its own support in the form of a square piece of polymer film of 8 mm side length and is glued to a conventional polyester packing tape together with similarly constructed limited areas (storage areas). Alternatively, however, the entire packaging tape based on the 3 to 5 have explained layer sequence, so that the entire packaging tape is arranged to store holographic information; such a variant may even be cheaper.

The storage area 11 has a polymer film configured as a storage layer 12 at the same time serves as a carrier (and forms in the above-mentioned variant, the support structure of the packing tape) and in the embodiment of biaxially oriented polypropylene (BOPP) and has a thickness of 35 microns. The refractive index of bipolar oriented polypropylene can be locally changed by heating, which can be exploited to store information, as explained above. Preferably, the polymer film has 12 a thickness in the range between 10 microns and 100 microns, but other thicknesses are also possible. Examples of further advantageous materials for the polymer film 12 are mentioned above.

In the storage area 11 is information in the form of pits 14 stored. In the field of a pit 14 has the polymer film 12 a different refractive index than in the zones between the pits 14 , The term "pit" is here to be understood in terms of a changed area, that is more general than in its original meaning ("hole"). In this case, the information can be stored in a pit in binary coded form in that the refractive index assumes only two different values (one of the two values also having the refractive index in the polymer film 12 in the zones between the pits 14 can match). It is also possible in a pit 14 store the information in a continuously encoded form, with the refractive index within the pit 14 can take any value selected from a given range of values. Illustratively speaking, when stored in binary coded form, a pit is "black" or "white", while when stored in continuously coded form it can also assume all intervening gray levels (gradations of amplitude or phase).

In the embodiment has a pit 14 a diameter of about 0.8 microns. Other shapes than circular pits 14 are also possible, eg square or rectangular pits, but also other sizes. Preferably, the typical dimension of a pit is about 0.5 μm to 2.0 μm. The 3 So is a greatly enlarged view and only shows a section of the memory area 11 ,

In 4 is a section of the storage area 11 shown in a schematic longitudinal section, and not to scale. It can be seen that a pit 14 not over the full thickness of the polymer film 12 extends. In practice, due to the writing process for entering information in which the polymer film 12 in the field of a pit 14 is heated, the transition zone in the lower part of a pit 14 to the lower portion of the polymer film 12 continuous, ie the refractive index changes gradually in this zone and not as sharply demarcated as in 4 shown.

Below (ie behind) the polymer film 12 there is a reflection layer 16 , which consists of aluminum in the embodiment. The reflection layer 16 can also fulfill its function if it is much thinner than the polymer film 12 ,

On top of the polymer film 12 is an absorber layer 18 applied. In the execution Game has the absorber layer 18 the absorber dye Sudan red 7B whose molecules are embedded in a matrix of an optically transparent polymer, namely polymethylmethacrylate (PMMA). The absorber layer 18 has a thickness of 0.5 microns in the embodiment. Sudan Red 7B absorbs light in the wavelength range around 532 nm particularly well; this wavelength is for a writing beam of a laser lithograph for inputting information into the memory area 11 suitable. Examples of other materials of the absorber layer 18 are given above. Thus, green dyes, for example of the styryl family, are particularly suitable for light wavelengths of 635 nm or 650 to 660 nm or 685 nm at which the laser diodes of current DVD devices operate; Such laser diodes can be modulated directly, which significantly simplifies and reduces the cost of pulse generation. In the future, the range from 380 to 420 nm could be interesting, if corresponding blue laser diodes are to be had commercially and inexpensively. For this purpose, it is then preferable to use yellow absorber dyes, such as, for example, stilbenes substituted with weak donors and acceptors, donor-substituted nitrobenzenes or coumarin dyes.

The absorber layer 18 has a preferred optical density in the range of 0.2 to 1.0; however, other values are also conceivable. The optical density is a measure of the absorption, in this case based on the wavelength of the light of a writing beam. The optical density is defined as the negative decadic logarithm of the transmission through the absorber layer, which is the product of the extinction coefficient at the used wavelength of the write beam, the concentration of the absorber dye in the absorber layer 18 and the thickness of the absorber layer 18 matches.

The absorber layer 18 facilitates entering information into the memory area 11 , Because if a writing beam on the area of a pit 14 is focused, he is at least partially in the absorber layer 18 absorbed. The released heat is largely transferred to the polymer film 12 and thus causes a local change in the refractive index in the polymer film 12 in the area of the pit 14 , However, it is possible to dispense entirely with the use of very short laser pulses on the absorber dye.

To enter the storage area 11 To input information, phase information contained in a hologram of a memory object is first calculated as a two-dimensional array. This can be done as a simulation of a classical design for producing a photographically detected hologram in which coherent light from a laser after scattering on the memory object is made to interfere with a coherent reference beam and the resulting interference pattern is picked up as a hologram. The two-dimensional array (two-dimensional array) then contains the information required to drive the writing beam of a laser lithograph. In the embodiment, the laser lithograph has a resolution of about 50,000 dpi (ie, about 0.5 μm). The writing beam of the laser lithograph is in pulsed operation (typical pulse duration of about 1 microseconds to 10 microseconds with a beam power of about 1 mW to 10 mW for entering a pit 14 ) over the top of the storage area 11 guided to the desired information sequentially in the memory area 11 (or a preselected area of the memory area 11 ). The writing beam heats the absorber layer 18 corresponding to the two-dimensional array, thus creating the pits 14 as explained above.

In 5 is illustrated in a schematic way, as in the memory area 11 stored information can be read out. For this purpose, coherent light from a laser (preferably a wavelength that of the absorber layer 18 only slightly absorbed) on top of the storage area 11 directed. For the sake of clarity, this is preferably parallel incident coherent light in 5 only a small section shown, with 20 is designated (incident reading beam). In practice, the coherent light is a large area on the polymer film 12 directed and covers a range of eg 1 mm ² . For the reconstruction of the stored information must be of many pits 14 outgoing light will be detected. The intensity of the incident reading beam 20 is too weak to the refractive index in the polymer film 12 and thus to change the stored information.

The incident reading beam 20 For practical reasons, at an angle to the surface of the storage area 11 hits, gets to the interface 22 between the polymer film 12 and the reflective layer 16 reflected, so that a reflected reading beam 24 from the interface 22 going out while doing the pits 14 penetrates. As the local refractive index of the polymer film 12 depending on the pit 14 is different, the local optical path length is varied so that it comes to phase shifts. As a result, from the memory area 11 in the manner of a diffraction grating spherical waves 26 go out, containing the stored phase information. At some distance from the storage area 11 For example, a detector can detect a holographic image caused by interference of the spherical waves 26 comes about.

The effort required for the detector and the further processing of the detected holographic image depend on the type of storage object as already explained above. For reproducing machine-readable data (data pages), a CCD sensor connected to a data processing device is particularly suitable, while for a pure image reproduction a simpler detector is also useful, in particular if the image data is not to be further processed.

The storage area 11 except in the 4 recognizable layers have additional layers, for example above the absorber layer 18 a transparent protective layer. Below the reflective layer 16 is in the embodiment, an adhesive layer, with which the memory area 11 is glued to the conventional packing tape.

If e.g. an absorber dye invisible in visible light (the e.g. absorbed in the infrared) or no absorber dye is used or if an absorber layer after entering of information in the memory area is washed off, can be the storage area is largely transparent and very inconspicuous.

Based on 6 to 8th Another possibility for storing holographic information by means of a packaging tape is explained. In the embodiment, again, limited areas or memory areas fixed at predetermined intervals on a conventional packing tape are provided for storing the information. Alternatively, but again, the entire packaging tape based on the 6 to 8th illustrated layer sequence, so that the entire packaging tape is arranged to store holographic information, similar to the example described above.

In 6 a section of the memory area designated here by 31 is shown in a schematic longitudinal sectional view. The storage area 31 has a polymer film configured as a storage layer 32 on, which consists in the embodiment of biaxially oriented polypropylene (BOPP) and has a thickness of 50 microns. At the bottom of the polymer film 32 there is a 100 nm thick reflection layer 33 made of aluminium. Disturbing interference effects due to reflections on the top of the polymer film 32 and the reflective layer 33 may be avoided by appropriate measures as appropriate. When the entire packaging tape is arranged to store holographic information, the polymer film may simultaneously serve as a support structure, and an adhesive layer is preferably disposed under the reflection layer.

In the material of the polymer film 32 An absorber dye is included that absorbs light from a writing beam and converts it into heat. In the exemplary embodiment is Sudan Red as Absorberfarbstoff 7B which absorbs light in the wavelength range around 532 nm particularly well; this wavelength is for a writing beam of a laser lithograph for inputting information into the memory area 31 suitable. Examples of other absorber dyes are already given above. Alternatively, the absorber dye can also be present in a separate layer, similar to the absorber layer 18 from the example according to the 3 to 5 ; in this case, the absorber layer has a preferred optical density (see above) in the range of 0.2 to 1.0, but other values are also possible. If the absorber dye is distributed over the entire polymer film, a greater value for the optical density is recommended so that sufficient absorber dye is present in the surface zone of the polymer film which is to be heated particularly during the writing process.

The absorber dye facilitates the input of information into the storage area 31 , Because if a writing beam 34, for example, with the help of a lens 35 on the polymer film 32 is focused, and preferably in their surface zone, the light energy of the writing beam 34 particularly efficiently converted into heat. In 6 are two writing beams 34 and two lenses 35 drawn to the writing of information at two different locations of the polymer film 32 to illustrate. In practice, the writing beam moves 34 but preferably sequentially across the surface of the polymer film 32 , For example, a laser lithograph having a resolution of about 50,000 dpi (ie, about 0.5 μm) is suitable for inputting the information. The writing beam of the laser lithograph is in pulsed operation (typical pulse duration of about 1 microseconds to about 10 microseconds at a beam power of about 1 mW to about 10 mW for exposing or heating a body) over the top of the polymer film 32 guided, so usually in two spatial directions to the desired information sequentially in the memory area 31 (or a preselected area of the memory area 31 ).

7 shows the result of the action of the pulsed writing beam 34 , Because of the poor thermal conductivity of the material of the polymer film 32 In a narrow volume, there is a significant increase in temperature, which causes the surface structure of the polymer film 32 locally changed. In this way, a pit arises 36 ie the local area where information is stored. To every pit 36 belongs to a central depression 38 that of a peripheral posing 39 is surrounded. The difference in level between the lowest point of the depression 38 and the highest point of the posing 39 ie the local maximum height change of the surface structure in the pit 36 , is in 7 With H denotes. H is typically in the range of 50 nm to 500 nm. The distance between the centers of two adjacent pits 36 , ie the dot matrix R, is preferably in the range of 1 .mu.m to 2 .mu.m. In the embodiment has a pit 36 a diameter of about 0.8 microns. Other shapes than circular pits 36 are also possible. Preferably, the typical dimension of a pit is about 0.5 μm to 1.0 μm. In supervision, the polymer film looks 32 with the pits 36 similar to the representation in 3 ,

In a pit 36 For example, the information may be stored in binary coded form by taking only two different values (one of which is preferably 0). It is also possible in a pit 36 storing the information in continuously encoded form, where H is for a given pit 36 can take any value selected from a given range of values.

To enter the storage area 31 To input information, holographic information contained in a hologram of a memory object is first calculated as a two-dimensional array. This can be done, for example, as a simulation of a classical structure for producing a photographically detected hologram in which coherent light from a laser scattered by the memory object is made to interfere with a coherent reference beam and the resulting modulation pattern is picked up as a hologram , The two-dimensional array (two-dimensional array) then contains the information required to drive the write beam of a laser lithograph previously discussed above. When the writing beam of the laser lithograph in pulsed mode over the top of the memory area 31 is guided, it heats the polymer film 32 according to the two-dimensional array. This will be the pits 36 generated as seen above.

In 8th is illustrated in a schematic way, as in the memory area 31 stored information can be read out. For this purpose, coherent light from a laser (preferably a wavelength, which is the absorber dye in the polymer film 32 not or only slightly absorbed) on the top of the storage area 31 directed. (Alternatively, a very bright LED can be used, which may even lead to more favorable results, especially with regard to a reduction of so-called speckles noise.) For the sake of clarity, this is preferably parallel incident coherent light (incident reading beam) in 8th only a small section shown, namely the with 42 and 43 designated incident light waves. In practice, the coherent light is a large area on the polymer film 32 directed and covers a range of, for example, 1 mm ² . For the reconstruction of the stored information must be of many pits 36 outgoing light will be detected. The intensity of the incident reading beam is too weak to reflect the surface structure of the polymer film 32 and thus to change the stored information.

The light waves 42 and 43 have a solid phase Φ to each other. For practical reasons they fall at an angle on the top of the polymer film 32 , penetrate the polymer film 32 and become at the reflection layer 33 reflected, so that reflected light waves 44 and 45 from the reflection layer 33 go out and turn the polymer film 32 penetrate. As the local surface structure of the polymer film 32 over the pits 36 varies, there is a phase shift, and the reflected light waves 44 and 45 come out with a phase ψ, as in 8th illustrated. As a result, from the memory area 31 in the manner of a diffraction grating light waves go out in many directions in which phase information is included. At some distance from the storage area 31 For example, a detector can detect a holographic image that is caused by interference of these light waves and represents a reconstruction of the stored information.

The 9 and 10 illustrate another way for storing holographic information by means of a tape. This time, in the embodiment, the entire packing tape is set to store holographic information.

In 9 is a section of the with 51 designated packing tape shown in a schematic longitudinal section, and not to scale; holographic information is already entered. The packing tape 51 has a support structure 52 from one 40 μm thick polymer film of stretched polyvinyl chloride, on the underside of which a 25 μm thick or slightly thinner acrylic adhesive layer (which is in 9 not shown). On top of the support structure 52 is a reflection layer 54 made of aluminum of 100 nm thickness.

Above the reflection layer 54 a polymer matrix is arranged, in which dye molecules are embedded, whereby a dye layer 56 is trained. In the exemplary embodiment, the polymer matrix consists of polymethyl methacrylate (PMMA) and has a thickness of 1 μm. Other thicknesses are also possible. In the exemplary embodiment, the dye used is sudan red in a concentration such that the thickness of the dye layer 56 an optical density of 0.8, provided that the dye in the dye layer 56 do not change by exposure that is. Preferred values for the optical density are in the range of 0.2 to 1.0; however, other values are also conceivable. On the top of the dye layer 56 is a protective layer 57 applied.

In the packing tape 51 is information in the form of pits 58 The term "pit" as previously understood to mean a localized area changed. In the field of a pit 58 is the absorbency in the dye layer 56 unlike in the zones between the pits 58 , It can be in a pit 58 the information may be stored in binary coded form in that the absorption capacity assumes only two different values (one of the two values also having the absorption capacity in the dye layer 56 in the zones between the pits 58 can match). It is also possible in a pit 58 store the information in a continuously encoded form, with the absorbance within the pit 58 can accept any value selected from a given range of values.

In the embodiment has a pit 58 a diameter of about 0.8 microns. Other shapes than circular pits 58 are also possible, eg square or rectangular pits, but also other sizes. Preferably, the typical dimension of a pit is about 0.5 μm to 1.0 μm.

It can be seen that in the exemplary embodiment, a pit 58 not over the full thickness of the dye layer 56 extends. In practice, due to the writing method for inputting information in which the dye is in the dye layer 56 in the field of a pit 58 is changed by means of a focused writing beam, the transition zone in the lower part of a pit 58 to the lower portion of the dye layer 56 continuous, ie the absorption capacity changes gradually in this zone and not as sharply demarcated as in 9 shown. The same applies to the lateral edges of a pit 58 , Preferably, the distance of the lower portions of the pits 58 to the reflection layer 54 and the thickness of the dye layer 56 set up so that interfering interference and interference effects are avoided when reading the holographic information.

In the embodiment, in the manufacture of the packaging tape 51 first the reflection layer 54 made of aluminum on the support structure 52 evaporated, then the polymer matrix with the dye of the dye layer 56 applied with an anilox roller and finally the protective layer 57 laminated.

To get in the packing tape 51 To input information, similar to previously, holographic information contained in a hologram of a memory object is calculated as a two-dimensional array (amplitude modulation). This can be done, for example, as a simulation of a classical design for producing a photographically detected hologram in which coherent light from a laser after scattering on the memory object is made to interfere with a coherent reference beam and the resulting interference pattern is captured as a hologram. The two-dimensional array (two-dimensional array) then contains the information required to drive the writing beam of a laser lithograph. In the embodiment, the laser lithograph has a resolution of about 50,000 dpi (ie, about 0.5 μm). The writing beam of the laser lithograph is in pulsed operation (typical pulse duration of about 1 microseconds to 10 microseconds with a beam power of about 1 mW to 10 mW for entering a pit 58 ) over the dye layer 56 of the packaging tape 51 guided to the desired information sequentially in the packing tape 51 (or a preselected area of the packaging tape 51 ). The writing beam changes the dye in the dye layer 56 corresponding to the two-dimensional array, thus creating the pits 58 as explained above.

In 10 is illustrated in a schematic way, as in the packaging tape 51 stored information can be read out. For this purpose, coherent light from a laser (preferably a wavelength, which is the dye of the dye layer 56 significantly absorbed) on top of the tape 51 directed. For the sake of clarity, this is preferably parallel incident coherent light in 10 only a small section shown, with 60 is designated (incident reading beam). In practice, the coherent light is a large area on the dye layer 56 directed and covers a range of eg 1 mm ² . For the reconstruction of the stored information must be of many pits 58 outgoing light will be detected. The intensity of the incident reading beam 60 is too weak to dye in the dye layer 56 and thus to change the stored information.

The incident reading beam 60 , for practical reasons at an angle to the surface of the packaging tape 51 impinges, penetrates the dye layer 56 and will be at the interface 62 between the dye layer 56 and the reflective layer 54 reflected, so that a reflected reading beam 64 from the interface 62 emanates. This will be the pits 58 penetrated with their different local absorption capacity, which causes an amplitude modulation with periodically different light absorption. The incident reading beam 60 is thus deflected in a defined manner, with the result being that of the packing tape 51 in the manner of a diffraction grating spherical waves 66 emanating the stored holographic information such as dergeben. At some distance from the packing tape 51 For example, a detector can detect a holographic image caused by interference of the spherical waves 66 comes about. Also at the interface of the packaging tape 51 against air, the reading beam is reflected and possibly modulated (for clarity, not in 10 marked), but much weaker. Nevertheless, it should be ensured by suitable choice of materials and layer thicknesses that there is no disturbing interference between the different reflected rays.

If a dye which is invisible in visible light is used (the e.g. absorbed in the infrared), the packing tape can be largely transparent and very unobtrusive shape.

Next the possibilities for storing holographic data explained here by way of examples by means of a tape basically a packing tape also in connection with other holographic storage techniques use.

Claims (28)

Packaging tape for use as a holographic data carrier, the packaging tape ( 3 ; 3 ' ) a polymer film ( 12 ; 32 ; 52 ) and adapted to store holographic information. Packing tape according to claim 1, characterized in that the packaging tape is adapted to an article ( 1 ; 1' ) using the packaging tape ( 3 ; 3 ' ) is packable. Packing tape according to claim 2, characterized in that the packing tape is adapted to the article ( 1' ) using the packaging tape ( 3 ' ) and that after packaging the article ( 1' ) holographic information in the packing tape ( 3 ' ) can be entered. Packaging tape according to claim 2 or 3, characterized in that the packaging tape is adapted to holographic information in the packaging tape ( 3 ) and that after inspiration of the holographic information the object ( 1 ) using the packaging tape ( 3 ) is packable. Packaging tape according to one of claims 1 to 4, characterized in that the polymer film ( 12 ; 32 ; 52 ) is stretched, preferably biaxially stretched. Packaging tape according to one of claims 1 to 5, characterized in that the polymer film ( 12 ; 32 ; 52 ) has a material selected from the group consisting of polypropylene, polyvinyl chloride, polyester, polyethylene terephthalate, polyethylene naphthalate, polymethylpentene, polyimide. Packaging tape according to one of claims 1 to 6, characterized in that the packing tape ( 3 ; 3 '; 51 ) has an adhesive layer. Packaging tape according to one of claims 1 to 7, characterized in that the polymer film ( 12 ; 32 ) is locally changeable by heating and for storing holographic information about the local properties of the polymer film ( 12 ; 32 ) is set up. Packaging tape according to claim 8, characterized in that the refractive index of the polymer film ( 12 ) is locally changeable by heating, wherein optical phase information about the local optical path length in the polymer film ( 12 ) is storable and it is intended, the polymer film ( 12 ) when reading out information, preferably in transmission. Packaging tape according to claim 8, characterized in that the surface structure of the polymer film ( 32 ) is locally changeable by heating, wherein holographic information about the local surface structure of the polymer film ( 32 ) is storable. Packaging tape according to claim 9 or 10, characterized in that the polymer film ( 12 ; 32 ) is assigned an absorber dye, which is adapted to a writing beam for inputting information ( 34 ) at least partially absorb the heat generated thereby at least partially locally to the polymer film ( 12 ; 32 ). Packaging tape according to claim 11, characterized in that in the material of the polymer film ( 32 ) Absorber dye is included. Packaging tape according to claim 11 or 12, characterized in that the absorber dye in a separate absorber layer ( 18 ), wherein the absorber layer ( 18 ) preferably comprises a binder. Packaging tape according to one of claims 1 to 7, characterized in that the polymer film ( 52 ) a dye layer ( 56 ) with an image-changeable, preferably bleachable or destructible dye, wherein holographic information about the local absorption capacity in the dye layer ( 56 ) is storable. Packaging tape according to claim 14, characterized in that the dye layer ( 56 ) has a polymer matrix in which dye molecules are embedded, wherein the polymer matrix is preferably at least one of the following group selected polymers or copolymers comprises: polymethylmethacrylate, polyimides, polyetherimides, polymethylpentene, polycarbonate, cycloolefinic copolymer, polyetheretherketone. Packing tape according to claim 14 or 15, characterized that the dye is at least one of the following group chosen Dyes comprises: azo dyes, diazo dyes, polymethine dyes, Arylmethine dyes, aza [18] annulene dyes, triphenylmethane dyes. Packaging tape according to one of claims 1 to 16, characterized in that the packing tape ( 3 ; 3 '; 51 ) a reflection layer ( 16 ; 33 ; 54 ) adapted to reflect light for reading holographic information. Packing tape according to one of claims 1 to 17, characterized in that the packing tape is adapted to that for inputting holographic information into the packing tape ( 3 ; 3 '; 11 ; 31 ; 51 ) holographic information contained in a hologram of a memory object is calculated as a two-dimensional array and a writing beam ( 5 ; 5 '; 34 ) a writing device ( 4 ; 4 ' ), preferably a laser lithograph, on the packaging tape ( 3 ; 3 '; 11 ; 31 ; 51 ) and according to the two-dimensional arrangement is so controlled that the local properties of the packaging tape ( 3 ; 3 '; 11 ; 31 ; 51 ) according to the holographic information. Packing tape according to claim 18, characterized in that the packing tape is adapted to the holographic information in the form of pits ( 14 ; 36 ; 58 ) predetermined size is entered. Packing tape according to claim 19, characterized in that the packing tape is arranged to be in a pit ( 14 ; 36 ; 58 ) the holographic information can be stored in binary coded form. Packing tape according to claim 19, characterized in that the packing tape is arranged to be in a pit ( 14 ; 36 ; 58 ) the holographic information can be stored in continuously coded form, the local properties of the packaging tape ( 3 ; 3 '; 11 ; 31 ; 51 ) in the pit ( 14 ; 36 ; 58 ) are adjustable according to a value from a predetermined range of values. Packaging tape according to one of claims 1 to 21, characterized in that the packing tape ( 3 ; 3 '; 11 ; 31 ; 51 ) has stored holographic information. Packing tape according to one of claims 1 to 22, characterized in that the packaging tape is set up for reading out holographic information from the packaging tape ( 3 ; 3 '; 11 ; 31 ; 51 ) Light ( 20 ; 42 . 43 ; 60 ), preferably coherent light, over a large area on the packaging tape ( 3 ; 3 '; 11 ; 31 ; 51 ) and after reflection on the packaging tape ( 3 ; 3 '; 11 ; 31 ; 51 ) as a reconstruction of the holographic information contained in the irradiated area, a holographic image at a distance to the packaging tape ( 3 ; 3 '; 11 ; 31 ; 51 ) is detected. Packing tape according to claim 23, characterized that the packaging tape is set up so that the holographic Image of a CCD sensor connected to a data processing device is detectable. Packaging tape according to one of claims 1 to 24, characterized in that the packing tape ( 3 ; 3 ' ) a number of limited areas ( 11 ; 31 ) each configured to store holographic information. Packaging tape according to claim 25, characterized in that the limited areas ( 11 ; 31 ) at predetermined intervals on the packaging tape ( 3 ; 3 ' ) are arranged. Packaging tape according to one of claims 1 to 26, characterized in that the packaging tape is adapted to that of the packaging tape ( 3 ; 3 '; 11 ; 31 ; 51 ) is to be erased holographic information by destroying with a strong write beam. Packing tape according to one of claims 1 to 27, characterized that the polymer film is set up as a support structure of the packaging tape is.