DE102014214298B4 - Data storage for product markings - Google Patents

Abstract

Method for optically reading out data from a hologram (3) by rotating a scanning disc (7) with a reconstruction side (7a) and a detector side (7b) and from the hologram (3) a holographic reconstruction with bits spaced apart from one another on the reconstruction side (7a) of the scanning disc (7), the scanning disc (7) for scanning the bits has a strip-shaped optical area (30) elongated in a radial direction of the scanning disc (7), the optical area (30) being designed to be transmissive and is arranged between the reconstruction side (7a) and the detector side (7b) and a detector is arranged on the detector side (7b), or wherein the optical region (30) is reflective and is arranged on the reconstruction side (7a) and a detector ( 9) is arranged on the reconstruction side (7a), the optical area (30) the reconstructed bits during the rotational movement The scanning disc (7) is recorded one after the other and the reconstructed bits are sent to a detector (9) and the recorded bits are evaluated.

Description

The invention relates to a method for optically reading out data from a hologram and to an arrangement with a product with a hologram and with a reader.

Product marking systems are used nowadays in a wide variety of forms. Most common they are in the form of 1D or. 2D Barcodes that are printed directly on product packaging or are on labels that are glued to product packaging. Such 1D , 2D Barcodes have developed into a standard and are read by machine for example at supermarket checkouts for clear product identification or contain machine-readable information for logistical purposes, for example for parcel services. The application possibilities are diverse and extend to freely available software applications for smartphones. Systems also exist in which the information is stored in holographic form in a polymer label or in a heat-seal patch that is located on the product or its packaging. To obtain the information, a reading device provides a laser beam that illuminates the hologram. The resulting holographic reconstruction ultimately mostly reaches a two-dimensional camera chip. The information can then be recovered from the two-dimensional brightness distribution on the camera chip via image processing steps. In many cases, the brightness distribution is similar to that of conventional 2D barcodes.

Such optical product marking systems consist of a data carrier and a reading device and have in common that the data carrier or the product with the data carrier and the reading device on it do not have any mechanical connection and are only brought together for the reading process. Depending on the design of the application, deviations from the ideal position of the product and reader can occur in all three spatial directions and in all rotational directions. Furthermore, it can generally be stated that a reading device must be designed to be more complex, the more precise the position and angle of the data carrier on the reading device to one another must be maintained during the reading process. The complexity of a device typically correlates with its manufacturing costs.

If complete freedom of rotation when reading out the data carrier with respect to a product axis is desired in a stationary reading device, complex and therefore costly reading devices are usually required.

Readers that allow complete freedom of rotation with respect to a Z-axis are known, for example, from CD players in which it does not matter at which angle of rotation a CD is inserted into the reader.

From the DE 103 45 898 A1 a method for calculating and generating a computer-generated hologram and a storage medium with a computer-generated hologram and a reading device are known. A method is disclosed in which the point distribution of a computer-generated hologram and that of a macroscopic superstructure, which can contain directly readable information, are calculated and both point distributions are linked to form a point distribution to be written to a storage medium.

From the GB 2 182 820 A discloses a scanning disc for scanning with a high intensity light beam over a recording element. The scanning disk includes a translucent or transparent support, a plurality of grids on the support, and a series of timer markings near the periphery of the disk for generating clock signals.

From the US 2002 000 8888 A1 an information carrier in the form of a hologram is known, the holographic reconstruction of which generates concentric circles of different thicknesses and spacings and thus produces rotationally invariant images. The disadvantage of this is that the data read out with the aid of a line sensor only make up a small part of the holographic image. The holographic reconstruction generates the same information everywhere along a circle, which means that a considerable amount of space and energy is required for illumination.

It is therefore the object of the present invention to provide a method for reading out data as mentioned at the beginning, as well as an arrangement which makes it possible to read out data from the data carrier of a product by means of a reader, regardless of the angle of rotation of the product the reader is inserted.

With regard to the method, the object is achieved by a method according to claim 1 and an arrangement with a product with a hologram and a reading device according to claim 11. Accordingly, a holographic reconstruction is scanned from a hologram serving as a data carrier with bits spaced apart from one another on a reconstruction side of a scanning disk. The scanning disc has an optical area for scanning the bits and rotates, the optical area detecting the bits one after the other and evaluating the detected bits will. In the following, a bit means a bright point of light that is created by the holographic reconstruction and represents stored data of the hologram.

The method according to the invention makes use of the idea of holographically reconstructing data stored optically in a hologram on a two-dimensional reconstruction plane and displaying the optically stored data in a temporal sequence by rotating scanning of the two-dimensional holographic reconstruction. During the rotation of the scanning disc, individual bits of the holographic reconstruction are recorded one after the other. The bits are preferably a sequence of 0 and 1 bits, which is also referred to here as a sequence, in which the data are encoded.

In a preferred embodiment of the method according to the invention, the bits of the holographic reconstruction are mapped in the form of a segment of a circle or a circle on the reconstruction side. The optical area comprises an elongated transmitting and / or reflecting strip which guides the bit reconstructed on the strip in the holographic reconstruction to the at least one detector, or the detector is directed onto the strip. At most exactly one single bit is detected in the transmitting and / or reflecting strip. The bit is either a 0 bit, the detection of which is based on the fact that no signal is detected, or a 1 bit, the detection of which is based on the detection of a signal.

A bit sequence shown in the holographic reconstruction is continuously and repeatedly scanned by rotating the scanning disk. Determining the start bit of the sequence is problematic.

It is advantageous to generate a start trigger in the holographic reconstruction which is recognized while the method according to the invention is being carried out. The start trigger is a marking within the holographic reconstruction which is also stored in the hologram and which maintains its position relative to the rest of the holographic reconstruction regardless of the position of the product or the rotational position of the scanning disc. The detection of the start trigger defines a start bit and a start time. The bits detected after the start time are arranged in the chronological order of their detection starting from the start bit to the sequence, and the sequence is ended when the scanning disc has performed a complete 360 ° rotation and the start trigger is detected again. The start trigger can be a holographic reconstruction of a 1-bit which is arranged radially shifted to the circular segment-shaped arrangement of the 0- and 1-bits and which is independently detected by means of a further optical area which is separated from the optical area.

In principle, it is also conceivable to select a bit sequence as the start trigger that is part of the sequence, but as a result of which storage space for the data is lost.

The reconstructed bits are advantageously resolved by the reading device by adapting a width of the optical area in the direction of rotation to the width of a 1-bit.

In one embodiment of the invention, the sequence is generated in that the scanning disc is set to a constant speed, as a result of which an angular position of the scanning disc and the time are strongly correlated. 1-bits are measured at certain times and 0-bits are assigned to intermediate times if no signal is detected.

In order to minimize fluctuations in the rotational speed of the scanning disk and other disruptive influences, markings are preferably arranged along an outer circumference of the scanning disk, which are recorded, in particular counted, during the rotation. As a result, a speed-independent measure is made available with which the position of the scanning disc can be determined. The position of the scanning disc is determined by the number of markings it has passed through. A detected bit is assigned to the markings recognized at the time of detection or to the number of markings counted up to that point. The markings are linked to predetermined time intervals or points in time, for example spacing time intervals are assigned to successive markings so that a time interval or a point in time that has passed since a starting point can be deduced from the sum of the spacing time intervals. The measured 1-bits and 0-Bts are thus correlated with the times via the markings.

A plane of the scanning disk and a plane of the hologram can preferably be arranged tilted relative to one another. In another embodiment, both planes are arranged parallel to one another.

In the case of the tilted arrangement in particular, the reconstructed bits can form an elliptical arrangement on the reconstruction side. In this embodiment, a zero position of the scanning disk relative to the ellipse is preferably also recognized. A zero position transmitter arranged on the scanning disk itself can be used for this purpose be used. While the method is being carried out, the zero position transmitter is arranged in a fixed position relative to the optical area of the scanning disc. With it, the position of the major and the position of the minor semiaxis of the elliptical reconstruction in relation to the optical area of the scanning disc are recognized and included in the evaluation.

A plurality of detectors are preferably arranged in a ring in a first ring along the scanning disk. When the bits are detected, the sum of the detector signals of the transmitted or reflected holographic signal is determined, and a 1 bit is preferably recognized when a predetermined threshold value is exceeded, and a 0 bit is recognized when a threshold value is not reached. A second ring of detectors can be provided to detect the start trigger, the signals of which are also summed. The second ring is preferably provided concentrically to the first ring along the detector disk.
In the second aspect, the object is achieved by the arrangement with the features of claim 11, the arrangement having a product with a hologram which generates a holographic reconstruction having bits spaced apart, and a reading device with a receptacle for the product. The reading device comprises a laser beam which can be directed onto the hologram and which generates the holographic reconstruction on a reconstruction side of a scanning disk that is rotatable relative to the holographic reconstruction. The scanning disc has an optical area for scanning the bits. At least one detector is aimed at the optical area.

The arrangement is suitable for carrying out one of the above-mentioned methods. The product is preferably designed to be rotationally symmetrical about a Z-axis, and the product with the hologram functioning as a data carrier can be freely inserted in its rotational position relative to the Z-axis in the receptacle of the reading device, and the reading device enables it to be independent of the position of the Product to read out the data encoded in the hologram.

According to the invention, the scanning disc is rotatably mounted in the reading device for this purpose, the axis of rotation of the scanning disc and the free axis of rotation of the product preferably being arranged as an extension of one another along the Z axis.

The hologram is expediently arranged on an end face of the product, which is inserted into the reader in advance.

The optical region preferably comprises an elongated transmitting and / or reflecting strip, onto which the at least one detector is directed.

A plurality of detectors is preferably provided, which are advantageously directed one after the other with overlapping measuring spaces during the rotation of the scanning disk onto the optical area. The plurality of detectors can then be connected to one another via a summation circuit which sums the measurement signals of the individual detectors. As a result, there is advantageously no need to undertake an exact assignment of the measurement signals to a single detector, which is difficult in the case of overlapping measurement spaces.

The optical area is preferably elongated, strip-shaped in the radial direction of the scanning disk. During the rotation of the scanning disk, the optical area scans the holographic reconstruction on its circular path.
In the radial direction, either exactly one 1 bit or exactly one 0 bit is generated on the reconstruction side of the scanning disc in the holographic reconstruction. Further 1-bits or 0-bits can be holographically reconstructed outside the optical area, for example in the form of start triggers.

The strip has a width in the direction of rotation which is adapted to an extent of the reconstructed bit. Preferably the strip is slightly narrower than the diameter of a circular 1-bit.

The strip is expediently made transparent, and the reading device has at least one detector which is arranged on the detector side of the scanning disc opposite the reconstruction side.

A plurality of detectors, advantageously a plurality of detectors, are preferably arranged on the detector side in a circle around the axis of rotation of the scanning disc and connected to one another in a summation circuit. The detectors detect only a 1-bit or a 0-bit by summing up their detector signals. If the scanning disc rotates at a constant speed for a period of time, points in time can be assigned to the measured 1 and 0 bits. The time allocation is the sequence.

In some embodiments of the invention, the optical region is designed to be reflective, and the at least one detector is arranged on the reconstruction side. It is also conceivable for the scanning disk to have a further optical area in the radial direction in addition to the optical area, preferably also in the form of a strip. The optical areas and the rest optical areas can each be designed to be reflective or transparent. In particular, the optical areas can also be transparent and the further optical area reflective, or vice versa; they can also all be constructed identically.

In a preferred development of the invention, the holographic reconstruction has a start trigger, and the bits following the start trigger in the opposite direction of rotation form the one-dimensional sequence. The start and end of the sequence are defined by the start trigger. The further optical area can be determined for the detection of the start trigger. The further optical area is preferably provided on the scanning disk with a radial offset to the optical area.

A beam splitter is preferably provided in the beam path between the laser and the hologram. In this arrangement, the hologram plane and the reconstruction plane of the scanning disk are advantageously arranged parallel to one another. In this embodiment, the holographic reconstruction is preferably an exactly circular arrangement of 1-bits and 0-bits.

Markings, which are detected during the rotation, are preferably arranged along an outer circumference of the scanning disk. The markings can be teeth or reflective imprints or the like, which are preferably provided equidistantly along the outer circumference and can be detected, for example, by means of a forked light barrier. This provides a speed-independent measure with which the position of the scanning disk can be determined in an evaluation device and which allows the detected bit to be assigned to a point in time.

In a further embodiment of the reading device of the arrangement according to the invention, the reconstruction plane and the hologram plane are arranged tilted relative to one another. In this embodiment, the holographic reconstruction is preferably an elliptical arrangement of 1-bits and 0-bits. The scanning disk preferably has a zero position transmitter which detects the position of the optical area and / or the further optical area in relation to the long and short semiaxis of the elliptical holographic reconstruction. The zero position transmitter can be a marking that differs from the other markings, for example a particularly wide tooth or a particularly wide printing.

• 1 einen schematischen Aufbau einer ersten Ausführungsform eines erfindungsgemäßen Lesegerätes mit eingelegtem Produkt,
• 2a 64 halbkreisförmig angeordnete gültige Bit-Positionen,
• 2b eine Berechnungsvorlage eines binären Fourier-Hologramms mit kreisförmiger Bitanordnung,
• 2c eine vollständige holographische Rekonstruktion eines binären Fourier-Hologramms mit Berechnungsvorlage aus 2b,
• 3a eine Abtastscheibe mit Streifen,
• 3b eine seitliche Ansicht der Abtastscheibe entlang der Linie Illb-Illb in 3a,
• 4a- 4c verschiedene Anordnungen von Fotodetektoren,
• 5 einen beispielhaften, zeitlichen Verlauf der gemessenen Gesamtintensität summierter Fotodetektorsignale,
• 6a eine Abtastscheibe mit 2 Zähnen,
• 6b eine Abtastscheibe mit 32 Zähnen,
• 6c eine Abtastscheibe mit 32 reflektierenden Bedruckungen,
• 7 eine schematische Ansicht einer zweiten Ausführungsform des Lesegerätes mit eingelegtem Produkt,
• 8 eine Abtastscheibe mit Nullpositionsgeber,
• 9a eine Berechnungsvorlage eines binären Fourier-Hologramms mit kreisförmiger Bitanordnung mit Starttrigger,
• 9b eine vollständige holographische Rekonstruktion des binären Fourier-Hologramms mit Berechnungsvorlage aus 9a,
• 10a eine Abtastscheibe mit einem weiterem Streifen und einem Nullpositionsgeber,
• 10b eine Fotodetektoranordnung mit zwei Ringen an Fotodetektoren für eine Abtastscheibe in 10a,
• 11 einen gemessenen Intensitätsverlauf des ersten und zweiten Ringes an Detektoren in 9b,
• 12a zwei Abwandlungen der ersten Ausführungsform des Lesegerätes in 1 mit eingelegtem Produkt,
• 12b zwei Abwandlungen der zweiten Ausführungsform des Lesegerätes in 7.

The invention is described on the basis of several exemplary embodiments in 22 figures, which show:

• 1 a schematic structure of a first embodiment of a reader according to the invention with an inserted product,
• 2a 64 valid bit positions arranged in a semicircle,
• 2 B a calculation template for a binary Fourier hologram with a circular bit arrangement,
• 2c a complete holographic reconstruction of a binary Fourier hologram with a calculation template 2 B ,
• 3a a scanning disc with stripes,
• 3b a side view of the scanning disc along the line Illb-Illb in 3a ,
• 4a - 4c different arrangements of photo detectors,
• 5 an exemplary temporal course of the measured total intensity of summed photodetector signals,
• 6a a scanning disc with 2 teeth,
• 6b a scanning disc with 32 teeth,
• 6c a scanning disc with 32 reflective prints,
• 7th a schematic view of a second embodiment of the reader with inserted product,
• 8th a scanning disc with zero position encoder,
• 9a a calculation template for a binary Fourier hologram with a circular bit arrangement with start trigger,
• 9b a complete holographic reconstruction of the binary Fourier hologram with a calculation template 9a ,
• 10a a scanning disc with another strip and a zero position encoder,
• 10b a photodetector arrangement with two rings of photodetectors for a scanning disc in FIG 10a ,
• 11 a measured intensity profile of the first and second ring on detectors in 9b ,
• 12a two modifications of the first embodiment of the reader in FIG 1 with inserted product,
• 12b two modifications of the second embodiment of the reader in FIG 7th .

The drawings are not to scale. 1 shows the position of a product 1 that into a reader 2 is inserted. The reader 2 is only shown in essential features and in principle. The product is shaped like a tetrahedron in a cross section in an XZ plane in an outer contour and is rotationally symmetrical about a Z axis. On the smaller one, one on the reader 2 facing end of the inserted product 1 is a flat hologram 3 outside of the product 1 visibly applied. In the hologram 3 stored information is by means of the reader 2 read out.

The reader 2 includes a laser diode 4th who have favourited coherent laser light towards a converging lens 5 gives. The collecting lens 5 essentially focuses the laser light on a scanning disc 7th . The collecting lens 5 is on a beam splitter 6th directed at an angle of 45 ° with respect to a lens plane of the converging lens 5 is arranged. On a hologram page 6a of the beam splitter 6th (in the 1 the top right outside of the beam splitter 6th ) is determined by the reflection rate of the beam splitter 6th certain proportion of the incident laser light on the hologram 3 reflected. The non-reflected part of the laser light passes through the beam splitter 6th and is not used any further. A 50% beam splitter is used here, which accordingly has a reflection rate of 50%.

That from the hologram 3 reflected light is in turn on the hologram side 6a of the beam splitter 6th directed. On the beam splitter 6th traversing portion of the laser light generated on a reconstruction side 7a the rotating scanning disc 7th a sharp holographic reconstruction. The holographic reconstruction on the reconstruction page 7a the scanning disc 7th is evaluated. Distances of the construction, i.e. distances between laser diodes 4th and converging lens 5 , between converging lens 5 and beam splitter 6th , Beam splitter 6th and hologram 3 as well as between hologram 3 and scanning disc 7th are dimensioned so that the holographic reconstruction creates a sharp image on the reconstruction side 7a generated.

This in 1 as well as the hologram used in the further embodiments 3 can be a laser lithography hologram, but also an embossed hologram. Basically, the way in which the hologram is made is important 3 itself no specific requirements.

In the embodiment according to 1 a binary Fourier hologram is used. 2c shows a rectangular section of the holographic reconstruction of the binary Fourier hologram. Midpoints M. the 2a to 2 B correspond to the center M. , which is also the pivot point of the scanning disc 7th is. In the centre M. the scanning disc 7th if the continuous laser beam also hits it, it is also referred to as a 0th order holographic reconstruction. The first order holographic reconstruction consists of 1-bit and 0-bit points that are circular around the center point M. are arranged and on the reconstruction side 7a the rotating scanning disc 7th are shown sharp and spaced from each other.

The Fourier hologram is in figure 2c calculated numerically. In the holographic reconstruction, an essentially arises around the center M. point symmetrical image. In 2 B a calculation template for a binary Fourier hologram with a circular bit arrangement is shown. 2c shows the one around the center M. Point-symmetrically doubled, real holographic reconstruction. Half the holographic reconstruction according to 2 B shows a sequence of 32 1-bits and 32 0-bits along a semicircle. Valid positions of the bits along a semicircle are in the 2a shown. The information to be read out is coded in the sequence of 1 and 0 bits.

The rotating scanning disc 7th is in 3a shown in a top view. It has a stripe 30th on, through the one on the reconstruction page 7a the scanning disc 7th focused bits through the scanning disc 7th penetrate through. On one of the beamsplitters 6th away from the detector side 7b the scanning disc 7th is a scattering element 31 arranged. The scattering element 31 is in 3a represented by dashed lines. The scattering element 31 is in the beam path of the strip 30th provided below. 3b shows a sectional view along the line Illb-Illb in 3a . The scanning disc 7th is opaque to the laser light, the strip 30th laser light is made transparent. One width of the strip 30th in the circumferential direction is dimensioned so that that on the reconstruction side 7a focused 1-bits about the width of the stripe 30th correspond so on the strip 30th 1-bits focused the strip 30th essentially completely penetrate and the entire light energy of the 1-bit then in the scattering element 31 is spread in the forward direction. 0 bits naturally do not generate a scattering cone, since they do not cause any light to strike the reconstruction side 7a correlate the scanning disc.

The scattering element 31 generated according to 1 a scatter cone 8th the one through the strip 30th urgent holographic reconstruction. The scatter cone 8th is so far that at least part of the light of the scatter cone 8th every rotary position of the scanning disc 7th from at least one photodetector 9 is detected, the one on the reconstruction side 7a away from the detector side 7b the rotating scanning disc 7th is arranged. The scanning disc 7th is powered by an electric motor 10 over a wave 11 driven. The wave 11 is central at the midpoint M. on the scanning disc 7th attached. The wave 11 is perpendicular to the Arranged hologram plane and runs here in the Z direction. A scanning disk plane and a hologram plane are in 1 arranged parallel to each other.

In the 4a - 4c are possible arrangements of photodetectors 9 on the detector side 7b the scanning disc 7th shown. Especially in 4a assign the photodetectors 9 a large distance from each other, but it has been found experimentally that such a distance of the photodetectors 9 sufficient to with the sufficiently wide scatter cone 8th to still detect a light signal and thus measure a 1-bit. The photo detectors 9 are switched in such a way that at a certain point in time the intensities of the on all photodetectors 9 the arrangement of incident light are summed and only a total intensity I is measured. It is not registered which photo detector 9 measured the intensity signal. If the measured total intensity I is above a predetermined threshold value, the measured total signal is correlated with a 1-bit, i.e. an evaluation circuit outputs a 1-bit as the measurement signal, while if the total intensity I falls below the threshold value, a 0-bit is detected as the measurement signal becomes. The distances between the photodetectors 9 from each other and the scatter cone 8th of the scattering element 31 are coordinated in their effect so that the same intensity peaks as possible are generated when a 1-bit is measured. Naturally, the intensity of the measured 1-bits depends on the position of the scanning disc 7th different, in particular the intensity is lower when the stripe 30th while measuring a 1-bit between two photodetectors 9 is positioned because then only the edges of the scatter cone 8th can be detected while in the event that the strip 30th during the measurement in the beam path in the middle in front of one of the photodetectors 9 is arranged, almost the entire intensity of the scatter cone 8th by the respective photodetector 9 is detected.

5 shows an idealized time course of the measured total intensity I of the summed photodetector signals. In the 5 measured total intensity I at points in time t _1,2,4,7,9 and t ₁₁ corresponds to a measured 1 bit. The measured total intensity at points in time t _3,5,6,8,10 corresponds to a measured 0 bit. In reality, the level of the measured total intensity I is not exactly the same, but, as described above, depending on the position of the strip 30th relative to the photo detectors 9 variable, but after evaluation of the intensity signals it can be recognized as a 1-bit or a 0-bit signal of a binary sequence by exceeding or falling below a threshold value.

The rotation of the scanning disc 7th , ie an angular position of the strip 30th and a time t must be strongly correlated with one another in order to enable an exact evaluation. The circularly arranged binary sequence in the holographic projection is created by rotating the scanning disc 7th converted into a one-dimensional, temporal binary sequence. There must therefore be angular positions of the scanning disc 7th and thus points in time are assigned to the bits. A regulating or correcting device is necessary, which must intervene if the rotational speed of the scanning disc changes 7th changed.

For this purpose it is conceivable, for example, to use a servo motor 10 to be used as an electric drive that includes an encoder system that records the number of revolutions per unit of time and automatically adjusts it to a specified value in the event of changes. Servo motors are disadvantageous 10 expensive to buy.

The scanning disc 7th can be used to create your own encoder system according to 6a and 6b two, a larger number or a plurality of along an outer circumference of the scanning disc 7th arranged teeth 60 exhibit. According to 6b are 32 teeth 60 intended. The succession of tooth 60 and the gap is detected by a fork-shaped light barrier with photosensor and photodiode and counted by a counter. The teeth 60 have the same width along the circumference and adjacent teeth 60 an equal distance from each other. This will take the measurements of 1-bits and 0-bits through the strip 30th in the 6b applied along a tooth axis, and the number of teeth passing through the light barrier 60 is correlated with a defined period of time.

A third embodiment of an encoder system is shown in 6c shown. Here light-reflecting sections alternate 61 and light absorbing portions 62 along the outer circumference of the scanning disc 7th from. A measurement of the reflective sections 61 takes place, for example, by a light-emitting diode (not shown) or a laser and a sensor (not shown) arranged on the side of the light-emitting diode or the laser.

7th represents a second embodiment of the reading device according to the invention 2 There is no beam splitter in the second embodiment 6th intended. The beam path differs from that of the first embodiment 1 from.

That from the laser diode 4th emitted laser light now does not strike the plane of the hologram perpendicularly 3 , but at an angle of incidence α . The one from the hologram 3 in one corresponding failure angle α reflected laser light hits the image surface 7a the scanning disc 7th . Angle of incidence and angle of reflection α of light on the hologram 3 should be less than α = Deviate 60 ° from the vertical.

Because the hologram plane and the reconstruction side 7a the scanning disc 7th are not arranged parallel to one another, arises in the holographic reconstruction of the same hologram 3 , that with a parallel arrangement of the hologram plane and the scanning disc 7th an exactly circular binary sequence according to 2c has formed an elliptical arrangement of the binary sequence on the reconstruction side 7a the scanning disc 7th .

8th shows a possible design of a scanning disc 7th for evaluating the holographic reconstruction of the embodiment according to 7th . Here is the strip 30th in the radial direction of the scanning disc 7th elongated, so that the 1 and 0 bits also in an elliptical holographic reconstruction with a corresponding angular position of the scanning disc 7th in the passage area of the strip 30th can be focused. The scanning disc 7th in 8th has a number of teeth that are identically wide in the circumferential direction 60 on showing a correlation between sequence of 1 and 0 bits and the teeth 60 and the time correlated with it t produce. In addition, there is a zero position encoder 80 in the form of a widened tooth 60 intended. The zero position encoder 80 makes it possible to adjust the angular position of the scanning disc with the help of the fork light barrier described above 7th towards the reader 2 and thus in particular to be recognized in relation to a long and short semiaxis of the elliptical holographic reconstruction.

The 9a and 9b show a holographic reconstruction with a start trigger 90 . 9a again represents the holographic reconstruction of a binary Fourier hologram, and it is the point-symmetrical arrangement of the binary sequence of 9a . The start trigger 90 has the function of marking the start bit of the 1 and 0 bit sequence of the holographic reconstruction.

The reader according to the invention 2 has a receptacle (not shown) that is rotationally symmetrical about the Z axis. The product, which is rotationally symmetrical about the Z axis, can be inserted into the receptacle 1 can be inserted in any angular position around the Z-axis. During the rotation of the scanning disc 7th by means of the shaft aligned parallel to the Z axis 11 1 and 0 bits are continuously generated. It is therefore necessary to define a start bit from which the bit sequence is defined, which then changes with the continuous rotation of the scanning disc 7th around its center M. continuously repeated.

The start bit can be defined, for example, by a predetermined sequence of 1 and 0 bits that precedes the start bit. However, this means that memory space for information is lost.

Another possibility is a mechanical design of the scanning disc 7th according to 10a which in cooperation with a holographic projection according to 10b the start bit of the bit sequence is clearly defined by adding another strip 100 is provided, which is spaced in the radial direction from the strip 30th into the scanning disc 7th is introduced. The further strip 100 detected when the scanning disc rotates 7th the start trigger 90 , but not the holographic reconstruction of the bit sequence arranged in a circle. The further strip 100 can be in radial extension of the strip 30th or in other angular positions relative to the strip 30th be arranged. The stripe 30th and the further strip 100 can be used as transparent strips 30th , 100 or as reflective strips 30th , 100 be trained. There can also be a combination of both.

The 10b shows an arrangement of photodetectors 9 , 101 . There are two concentric rings of photo detectors 9 , 101 intended. The outer ring of photo detectors 9 detects, as shown in the aforementioned embodiments, the 1 and 0-bit sequence, while the inner ring of photodetectors 101 exclusively for the detection of the start trigger 90 is provided.

The 11 shows the results of the measurement of total intensities I of the outer and inner rings of the photodetectors 9 , 101 . By measuring the start trigger 90 becomes a start time t ₀ clearly defined, and from there the bit sequence of 1-bits and 0-bits can be defined.

In the 12a and 12b are modifications of the first embodiment of FIG 1 or the second embodiment in 7th of the reader according to the invention 2 shown. The same reference symbols again denote the same components and features. In both embodiments the strip is 30th not made transparent, but scattering in reflection, ie the light reflected by the hologram is on the reconstruction side 7a the scanning disc 7th reconstructed. The beam path penetrates the scanning disc 7th thus not, but the light is on the reconstruction side 7a on the reflective strip 30th reflected and also scattered by means of a scattering element.

The 12a shows in the same illustration two different embodiments of possible detector arrangements. In one embodiment, there are photodetectors 9 circular in the area of the front of the inserted product 1 and thus circular on the outside around the hologram 3 of the inserted product 1 arranged. The photo detectors 9 are with the product 1 not tightly connected, but they are along the perimeter of the hologram 3 firmly to the rest of the reader 2 connected arranged.

In the other embodiment of the 12a are instead photo detectors 9 the laser diode 4th opposite on the beam splitter 6th intended. The photo detectors 9 are intended to be used by the reconstruction side 7a the scanning disc 7th to the beam splitter 6th reflected back and there on the back 6b to the photo detectors 9 (in 12a to the left) to measure reflected light. Preferably the laser diode is 4th exactly opposite no photo detector 9 provided so that the 0-th order laser beam does not hit a photodetector 9 meets.

12b FIG. 13 shows a modification of the second embodiment in FIG 7th of the reader according to the invention 2 . There is at least one photo detector 9 next to the hologram 3 of the product placed in the receptacle 1 provided and another photodetector 9 is the reconstruction side 7a the scanning disc 7th opposite next to the converging lens 5 arranged. It has been shown that such a detector arrangement for measuring the total intensity I of the reflective strips 30th reflected laser beam is suitable. The scattering cone of the reflected scattered laser light must be large enough to be detected by at least one of the photodetectors 9 to be detected.

List of reference symbols

1

product

2

Reader

3

hologram

4th

Laser diode

5

Converging lens

6

Beam splitter

6a

Hologram side

6b

back

7th

Scanning disc

7a

Reconstruction page

7b

Detector side

8th

Scatter cone

9

Photo detector

10

Electric motor / servo motor

11

Shaft / motor shaft

30th

Stripes / optical area

31

Scattering element

60

teeth

61

Light reflecting sections

62

Light absorbing sections

80

Zero position transmitter

90

Start trigger

100

further stripes / further optical area

101

Photo detector

M.

Focus

t

time

t ₀

Start time

t _{1 - 11}

Points in time

α

Angle of incidence = angle of reflection

Claims (18)

Method for the optical readout of data from a hologram (3) by rotating a scanning disc (7) with a reconstruction side (7a) and a detector side (7b) and a holographic reconstruction with bits spaced apart from one another is imaged from the hologram (3) on the reconstruction side (7a) of the scanning disc (7), the scanning disc (7) for scanning the bits has a strip-shaped optical region (30) which is elongated in a radial direction of the scanning disc (7), wherein the optical area (30) is designed to be transmitting and is arranged between the reconstruction side (7a) and the detector side (7b) and a detector is arranged on the detector side (7b), or wherein the optical area (30) is designed to be reflective and on the Reconstruction side (7a) is arranged and a detector (9) is arranged on the reconstruction side (7a), the optical area (30) detects the reconstructed bits one after the other during the rotational movement of the scanning disk (7) and the reconstructed bits are routed to a detector (9) and the recorded bits are evaluated. Procedure according to Claim 1 , characterized in that the detected bits are arranged in a one-dimensional sequence. Procedure according to Claim 2 , characterized in that the bits of the holographic reconstruction are circular segments on the Reconstruction side (7a) are arranged. and the optical region comprises an elongate transmitting and / or reflecting strip (30, 100) which guides the bit reconstructed on the strip (30, 100) to at least one detector (9). Procedure according to Claim 1 , 2 or 3 , characterized in that the holographic reconstruction is provided with a start trigger (90) and the start trigger (90) is recognized and a start time (to) is assigned to the start trigger and bits detected after the start time (t ₀ ) are arranged in the sequence. Method according to one of the preceding claims, characterized in that spatial distances between the reconstructed bits are recognized and are correlated with time distances between the measured bits. Method according to one of the preceding claims, characterized in that markings (60) are arranged along an outer circumference of the scanning disc (7), which are detected during the rotation and are assigned to the measured 1-bits and 0-bits, and the markings (60 ) are correlated with times (t _{1 -11} ) and the measured 1-bits and 0-bits are correlated with the times (t _1-11 ). Method according to one of the preceding claims, characterized in that a plane of the scanning disc (7) and a plane of the hologram (3) are arranged tilted relative to one another. Procedure according to Claim 7 , characterized in that the reconstructed bits form an elliptical arrangement on the reconstruction side (7a) and the scanning disc (7) is provided with a zero position transmitter (80) and a zero position of the scanning disc (7) relative to the ellipse is detected. Method according to one of the preceding claims, characterized in that the sum of detector signals from the detectors (9, 101) is determined and a 1-bit is recognized when a predetermined threshold value is exceeded and a 0-bit is recognized when the threshold value is undershot. Procedure according to Claim 9 , characterized in that the detectors (9) are arranged along a path swept by the optical region (30, 100) during the rotation and their detector signals are summed. Arrangement with a product (1) with a hologram (3), which generates a holographic reconstruction with bits spaced apart, and with a reader (2) with a receptacle for the product (1) and with a scanning disc (7) with a reconstruction side (7a) and a detector side (7b) and with a laser beam that is directed onto the hologram (3) and the holographic reconstruction on the relative to the holographic Reconstruction rotatable reconstruction side (7a) of the scanning disc (7) generated, wherein the scanning disc (7) has an elongated strip-shaped optical area (30) in a radial direction of the scanning disc (7) for scanning the bits, the optical area (30) being designed to be transmitting and between the reconstruction side (7a) and the detector side (7b) is arranged and a detector is arranged on the detector side (7b), or wherein the optical region (30) is reflective and is arranged on the reconstruction side (7a) and a detector is arranged on the reconstruction side (7a) wherein the optical area (30) detects the reconstructed bits one after the other during the rotational movement of the scanning disk (7), and with at least one detector (9) which is directed onto the optical area (30). Arrangement according to Claim 11 , characterized in that a plurality of detectors (9) is arranged along a path swept by the optical region (30) during the rotation and by a summation circuit which sums the detector signals. Arrangement according to Claim 11 or 12 , characterized in that the holographic reconstruction has a start trigger (90) and the scanning disc (7) has a further optical area (100) for detecting the start trigger (90) and an evaluation device which, when the start trigger (90) is detected, a start time ( to). Arrangement according to one of the Claims 11 to 13 , characterized in that markings (60) are arranged along an outer circumference of the scanning disc (7), which are detected during the rotation and which are linked to predetermined time intervals and that the evaluation device uses the markings ( 60) correlates with the times (t _{1 -11} ). Arrangement according to one of the Claims 11 to 14th , characterized in that the scanning disc (7) has a zero position transmitter (80) which detects the position of the optical area (30) and / or of the further optical area (100) in relation to the reading device (2). Arrangement according to Claim 11 to 15th , characterized in that the optical area (30) and / or the further optical area (100) has a width which corresponds to an extension of a reconstructed 1-bit. Arrangement according to one of the Claims 11 to 16 , characterized in that the scanning disc (7) has a scattering means (31) for the laser light on the optical area (30) and / or further optical area (100). Arrangement according to one of the Claims 11 to 17th , characterized in that a beam splitter (6) is provided in a beam path between the laser (4) and the hologram (3).

Images