WO2007115717A2 - Procédé et dispositif permettant de lire un hologramme créé par ordinateur - Google Patents

Procédé et dispositif permettant de lire un hologramme créé par ordinateur Download PDF

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Publication number
WO2007115717A2
WO2007115717A2 PCT/EP2007/002935 EP2007002935W WO2007115717A2 WO 2007115717 A2 WO2007115717 A2 WO 2007115717A2 EP 2007002935 W EP2007002935 W EP 2007002935W WO 2007115717 A2 WO2007115717 A2 WO 2007115717A2
Authority
WO
WIPO (PCT)
Prior art keywords
hologram
light
generated
reconstruction
reading
Prior art date
Application number
PCT/EP2007/002935
Other languages
German (de)
English (en)
Other versions
WO2007115717A3 (fr
Inventor
Stefan BORGSMÜLLER
Matthias Gerspach
Steffen Noehte
Kay Schulte-Wieking
Original Assignee
Tesa Scribos Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tesa Scribos Gmbh filed Critical Tesa Scribos Gmbh
Publication of WO2007115717A2 publication Critical patent/WO2007115717A2/fr
Publication of WO2007115717A3 publication Critical patent/WO2007115717A3/fr

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2286—Particular reconstruction light ; Beam properties
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2202—Reconstruction geometries or arrangements
    • G03H2001/2223—Particular relationship between light source, hologram and observer
    • G03H2001/2234—Transmission reconstruction
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2223/00—Optical components
    • G03H2223/14—Diffuser, e.g. lens array, random phase mask

Definitions

  • the invention relates to a method for reading out a computer-generated hologram and to a device for reading out a computer-generated hologram.
  • Computer-generated holograms consist of one or more layers of dot matrices or point distributions which, when illuminated with a preferably coherent light beam, lead to a reconstruction of the information encoded in the hologram.
  • the point distribution can be calculated here as an amplitude hologram, phase hologram or as a Kinoform Fresnel or Fourier hologram or another computer-calculated holographic form.
  • these are first calculated and then written with a suitable writing device by point-wise introduction of energy into a storage medium.
  • the resolution of the resulting dot matrix can, as already mentioned, be in the range below 1 ⁇ m.
  • holograms with a high resolution can be written in a small space, the information of which can only be read out by illuminating with a light beam and reconstructing the diffraction image.
  • the size of the holograms can be between less than 1 mm 2 and several 1 cm 2 .
  • holograms can be generated in series, which include, for example, serial numbers or production parameters. Such holograms can therefore be used in particular as security features or in the logistics for product tracking on packaging, credit cards, tickets or the like.
  • the security features of the hologram can be read out and the authenticity and individuality of the security feature can be checked in a simple manner.
  • the computer-generated holograms described above can be combined with directly visible information (microprint, microimages).
  • the mentioned microimages and micro-scripts themselves can be written independently of computer-generated holograms.
  • the dot distributions can also be generated as dot matrix holograms, wherein in each case individual small surface sections are generated as different diffraction structures of the dot matrix hologram.
  • DOE diffractive optical element
  • a laser beam in the visible wavelength range is usually meant.
  • the present invention is not limited to the application of visible light.
  • the invention can be applied to electromagnetic radiation in a wide wavelength range.
  • a plurality of writing devices for writing computer-generated holograms are known from the prior art, which write in planar storage media the optical structures of the holgrams.
  • These writing devices use a laser beam which sequentially scans every single point of the dot matrix and optionally introduces light energy into the storage medium or not.
  • a plurality of reading devices are known, which are suitable for illuminating the hologram surface by means of a light beam and a suitable optical system to make the reconstruction visible or electronically representable and evaluable by means of recording means.
  • a suitable optical system to make the reconstruction visible or electronically representable and evaluable by means of recording means.
  • the present invention relates to the reading of transmission holograms inscribed on a storage medium, the surface of which is illuminated by a reading beam of a light source.
  • the diffracted by the structure of the hologram light field is detected in the beam direction behind the storage medium, wherein in a simple embodiment, a person simply looks into the beam and the reconstruction of the hologram is imaged on the retina of the person.
  • the present invention is therefore based on the technical problem of specifying a particularly simple and inexpensive method in which the observing person is sufficiently protected against excessive light intensities.
  • the above-mentioned technical problem is solved according to the invention by a method for reading a computer-generated hologram, in which a laser beam a reading beam is generated, is scattered by means of a lens the reading beam and that the surface of the hologram with only a part of the scattered Reading beam is illuminated.
  • the intensity of the laser light which strikes the hologram surface is reduced because a part, preferably a larger part of the laser light, is scattered out of the beam path by the diffusing screen and only one, preferably smaller part of the laser light is scattered the hologram surface hits.
  • the light field of the reconstruction is then sufficiently weak that a person can observe the reconstruction with the naked eye and without further optics in transmission without further protective measures.
  • the light has a frequency spectrum that is substantially larger, preferably at least 50 times larger, than the frequency spectrum of a laser.
  • a light is preferably generated by a light emitting diode (LED).
  • LED light emitting diode
  • the reconstruction of the hologram can be observed by a person without further optics in transmission.
  • a special eye protection is not necessary because of the low energy density of the light.
  • FIG. 1 shows the structure of a first device according to the invention for reading a computer-generated transmission hologram with a laser and a lens
  • FIG. 2 shows a representation of a reconstruction produced by means of the device shown in FIG. 1, FIG.
  • FIG 3 shows the structure of a second device according to the invention for reading out a computer-generated transmission hologram with a monochromatic LED (light-emitting diode),
  • FIG. 4 shows a representation of a reconstruction produced by means of the device shown in FIG. 3 when using a blue light-emitting diode
  • FIG. 5 shows a representation of a reconstruction produced by means of the apparatus shown in FIG. 3 when using a green light emitting diode
  • Fig. 6 is an illustration of a reconstruction using the device shown in Fig. 1 when using a white light emitting diode.
  • Fig. 1 shows the optical structure of a first device according to the invention. With the aid of a laser 2, a laser beam 4 is generated, which is scattered by means of an arranged in the beam path lens 6 in a certain angular range. As a result, the power of the laser light is distributed over a larger area of space.
  • a storage medium 8 with a computer-generated hologram 10 mounted thereon is only detected by a small part of the laser power due to the scattering of the laser light.
  • a person need not make a special protection of the eye and can observe the reconstruction, even if the laser beam 4 in itself has a much too high intensity to observe it directly with the eye.
  • commercially available lasers with output powers of up to 10 mW can also be used.
  • Fig. 2 shows a reproduction of a hologram containing the numerical sequence 12345 as information. Despite the scatter, a clear reconstruction can be observed.
  • FIG. 3 shows the construction of a second device according to the invention.
  • a light-emitting diode 11 generates a light beam with which a computer-generated hologram 10 arranged on a storage medium 9 is illuminated.
  • the light field thus generated in transmission can be observed directly by a naked-eye observer 8, because even without an intermediate hologram, the output power of the light beam is not too large to be observed directly with the eye. Due to the greater spectral distribution of the light generated by a light emitting diode but it comes to different diffraction direction for different frequencies of light, so to a. chromatic aberration. This is illustrated by FIGS. 4 to 6.
  • a hologram also containing the information of the number sequence 12345 is first illuminated with a blue light-emitting diode. The resulting reconstruction is shown along with the zeroth order (light spot in the lower half of the image as a reference) as orientation in FIG.
  • Fig. 5 shows the reconstruction of the same hologram when illuminated with a green LED, wherein in comparison to FIG. 4, an enlargement is proportional to the increase of the wavelength and thus a shift of the reconstruction relative to the zeroth order upwards.
  • Fig. 6 shows the reconstruction of the same hologram when illuminated with a white light emitting diode.
  • the reconstruction of the 12345 series is heavily blurred due to chromatic aberration.
  • Figs. 4 to 6 The effect of the chromatic aberration shown in Figs. 4 to 6 is exaggerated.
  • a single colored light emitting diode has a much narrower frequency spectrum than the distance between the colors blue (FIG. 4) and green (FIG. 5).
  • the frequency distribution is smaller, but nevertheless significantly larger than in the case of a laser, this leads to a smearing of the reconstruction due to the chromatic aberration, which is disadvantageous in particular with small details of the reconstruction.
  • the chromatic aberration is greater, the greater the diffraction angle, ie the greater the distance from the zeroth order, this can be taken into account in the calculation of the computer-generated hologram in that the information to be reconstructed is contained only in a region of the reconstruction which does not exceed a certain distance to the zeroth order. This further reduces the smearing resulting from the chromatic aberration.

Abstract

La présente invention concerne un procédé permettant de lire un hologramme créé par ordinateur. Ce procédé consiste à produire un faisceau de lecture avec un laser. Cette invention est caractérisée en ce que le faisceau de lecture est diffusé à l'aide d'un diffuseur et en ce que la surface de l'hologramme n'est éclairée qu'avec une partie du faisceau de lecture diffusé.
PCT/EP2007/002935 2006-04-04 2007-04-02 Procédé et dispositif permettant de lire un hologramme créé par ordinateur WO2007115717A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE200610015608 DE102006015608A1 (de) 2006-04-04 2006-04-04 Verfahren und Vorrichtung zum Auslesen eines computergenerierten Hologramms
DE102006015608.0 2006-04-04

Publications (2)

Publication Number Publication Date
WO2007115717A2 true WO2007115717A2 (fr) 2007-10-18
WO2007115717A3 WO2007115717A3 (fr) 2008-03-27

Family

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Application Number Title Priority Date Filing Date
PCT/EP2007/002935 WO2007115717A2 (fr) 2006-04-04 2007-04-02 Procédé et dispositif permettant de lire un hologramme créé par ordinateur

Country Status (2)

Country Link
DE (1) DE102006015608A1 (fr)
WO (1) WO2007115717A2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102298310A (zh) * 2010-06-23 2011-12-28 中钞特种防伪科技有限公司 模压全息图的成像照明系统及其缺陷检测方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3436230A1 (de) * 1984-09-29 1986-04-03 Matthiesen, geb. Sievers, Gerda, 2000 Hamburg Anordnung zur ausleuchtung von transmissions-hologrammen
EP0231464A2 (fr) * 1986-01-07 1987-08-12 Gerd Dipl.-Ing. Seele Procédé et dispositif pour la reconstruction achromatique d'hologrammes de transmission
WO2002084588A1 (fr) * 2001-04-12 2002-10-24 Tesa Scribos Gmbh Dispositif de lecture directe pour hologrammes, en particulier pour hologrammes numeriques

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2215746A1 (de) * 1972-03-30 1973-10-11 Siemens Ag Verfahren zum sequentiellen aufzeichnen und auslesen von daten auf einem speicherband
US4602844A (en) * 1984-10-01 1986-07-29 California Institute Of Technology Monochromatic incoherent light holography

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3436230A1 (de) * 1984-09-29 1986-04-03 Matthiesen, geb. Sievers, Gerda, 2000 Hamburg Anordnung zur ausleuchtung von transmissions-hologrammen
EP0231464A2 (fr) * 1986-01-07 1987-08-12 Gerd Dipl.-Ing. Seele Procédé et dispositif pour la reconstruction achromatique d'hologrammes de transmission
WO2002084588A1 (fr) * 2001-04-12 2002-10-24 Tesa Scribos Gmbh Dispositif de lecture directe pour hologrammes, en particulier pour hologrammes numeriques

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102298310A (zh) * 2010-06-23 2011-12-28 中钞特种防伪科技有限公司 模压全息图的成像照明系统及其缺陷检测方法
CN102298310B (zh) * 2010-06-23 2014-11-19 中钞特种防伪科技有限公司 模压全息图的成像照明系统及其缺陷检测方法

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Publication number Publication date
DE102006015608A1 (de) 2007-10-18
WO2007115717A3 (fr) 2008-03-27

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