EP0660959A1 - Detecteur de donnees a surface de diffraction - Google Patents

Detecteur de donnees a surface de diffraction

Info

Publication number
EP0660959A1
EP0660959A1 EP93918801A EP93918801A EP0660959A1 EP 0660959 A1 EP0660959 A1 EP 0660959A1 EP 93918801 A EP93918801 A EP 93918801A EP 93918801 A EP93918801 A EP 93918801A EP 0660959 A1 EP0660959 A1 EP 0660959A1
Authority
EP
European Patent Office
Prior art keywords
diffracted
optical
beams
sensor
signal
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
EP93918801A
Other languages
German (de)
English (en)
Other versions
EP0660959A4 (fr
Inventor
Peter Samuel Atherton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mikoh Technology Ltd
Original Assignee
Mikoh Technology Ltd
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
Priority claimed from JP018157U external-priority patent/JPH0670558U/ja
Application filed by Mikoh Technology Ltd filed Critical Mikoh Technology Ltd
Publication of EP0660959A1 publication Critical patent/EP0660959A1/fr
Publication of EP0660959A4 publication Critical patent/EP0660959A4/fr
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
    • G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/002—Recording, reproducing or erasing systems characterised by the shape or form of the carrier
    • G11B7/0033—Recording, reproducing or erasing systems characterised by the shape or form of the carrier with cards or other card-like flat carriers, e.g. flat sheets of optical film
    • 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
    • G03H1/2249—Holobject 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
    • G03H2001/2244—Means for detecting or recording the holobject
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2210/00—Object characteristics
    • G03H2210/20—2D object
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2227/00—Mechanical components or mechanical aspects not otherwise provided for
    • G03H2227/05—Support holding the holographic record
    • G03H2227/06—Support including light source

Definitions

  • a known kinegram card contains a computer generated holographic pattern extending along one or more tracks across the card.
  • the pattern resembles a conventional hologram but is much brighter and can be made to display a greater degree of movement when viewed at different angles.
  • the card is used, for example when making a telephone call , it is inserted in a reader slot and the available balance is
  • __ displayed.
  • the equipment automatically emits metering pulses.
  • the pulses sequentially decrement the card by destroying each bit by thermal energy.
  • the hologram is read by directing at the pattern light, which is reflected. The angle of reflection is in a direction determined by the hologram.
  • a detector is positioned to be activated by the reflected light.
  • Swiss Patent 622896 (Application No 2995/7S) describes the use of a hologram, in which the reflected light includes a first reflected beam detected by a first sensor, while a second sensor detects scattered light reflected in a second direction. More particularly, the light reflected in the second direction includes a narrow beam and a diverging beam. The narrow beam is blocked so that only the diverging beam is delivered to the second sensor.
  • optical marks on numerical rollers of a counter mechanism.
  • the optical marks can be a reflective hologram or a refractive grid.
  • a reading beam is directed at each mark and a single beam reflected.
  • Each mark directs the reflected beam at a different angle, with a plurality of detectors being arranged to be illuminated by the appropriate beam.
  • Patent 604279 describes the use of discrete lo optical marks (which may consist of a diffractive grating or a hologram) which are erased to record information. There is little discussion of reading techniques and the properties of the optical marks.
  • European Patent Publication 0 015 307 (European Application 79104004J) describes the use of a stored value card.
  • the card has a series of optical marks arranged in i s discrete units. The marks are sequentially erased in order to decrease the value of the card.
  • Swiss Patent 638632 (Application No 929/79) also describes the use of optical marks on a card. The marks are arranged in a predetermined order and are used for identification purposes.
  • Swiss Patent Application 6836/81 shows the use of optical marks for the purposes of determining the authenticity of a document. The reading beam changes in wavelength which alters the direction of the refracted beam. A detector is then used to determine this change in direction as a means of determining the authenticity of the document.
  • European Patent Publication 0 057 271 (European Application No 81 109503.3) 5 describes the use of optical markings to produce two refracted narrow light beams. Measurement of the intensity of the light beams is used to verify the authenticity of the document.
  • European Publication No 0 366 585 (Application No 89108121 .8) discloses the use of diffraction gratings arranged in a bar code. However the bars are applied to the carrier o in a predetermined order in order to record information.
  • optical diffraction techniques still lend themselves to unauthorised use particularly unauthorised reproduction of the holograms, and/or are not suitable for normal commercial use.
  • a stored value system is one in which the user purchases a memory device which 5 represents usage of some service or facility up to a certain value.
  • a good example can be found in many telephone systems, where users can purchase a stored value card which allows usage of the telephone system up to a specified value.
  • a stored value system depends on being able to sell to the user a memory device which can be altered to reflect usage of the system.
  • This memory usually comes in the form of a card, a good example being a telephone card.
  • the requirements on this stored value card are that it should be inexpensive; it must contain a write-once stored value memory so that once the value of the card has been decremented, the decrement is permanent; it should resist copying or fraudulent production; and preferably it should be 5 capable of retaining a large number of the units of value for the system, so that the user does not have to replace the card too frequently.
  • optical memories are used in stored ⁇ o value telephone cards in some countries, but these are generally limited to a relatively small number (several hundred or so) of stored value units, making them unsuitable for a number of other potential applications.
  • a method of detecting information stored on an optical memory diffraction area said area having a diffraction surface adapted to provide a diffracted beam with an intensity pattern determined by the configuration of the surface, 0 said method including the steps of: subjecting said surface to a reading beam; positioning an optical sensor so as to be illuminated by the diffracted beam, said sensor being adapted to detect an intensity pattern in the diffracted beam; and activating said sensor to produce a signal indicative of said intensity pattern.
  • a device comprising: means to receive an item having an optical memory diffraction area, said area having a diffraction surface adapted to provide a diffracted beam with an intensity pattern determined by the configuration of the surface; light producing means to produce a light beam directed to illuminate said surface so o as to produce a diffracted light beam; and an optical sensor positioned to be illuminated by the diffracted light beam, said optical sensor being adapted to produce a signal indicative of the intensity pattern of the diffracted light beam.
  • Figure 1 is a schematic illustration of the important optical properties of a diffraction surface
  • Figure 2 is a schematic illustration of an example of a diffraction surface and a type of diffracted beam Intensity Pattern which may be produced by said diffraction surface;
  • Figure 3 is a schematic illustration of a device used to authenticate and read data recorded in or on a diffraction surface. 5 The following definitions apply to terms used herein.
  • Intensity Pattern means the optical Intensity Pattern, or intensity distribution, of a beam of light as projected onto a surface which intercepts said beam of light.
  • Pattern is normally represented graphically as a 3 dimensional plot of optical intensity versus position on said surface.
  • Features of an Intensity Pattern are usually referred to in ⁇ o terms of this 3 dimensional plot.
  • Signal Optical Feature means either a local maximum or a local minimum or a saddle point in an Intensity Pattern, neglecting the local and small scale effects of optical noise on said Intensity Pattern.
  • “Saddle Point” means a point in an Intensity Pattern which is a local maximum i s along one axis and a local minimum along an orthogonal axis.
  • FIG. 1 is a schematic illustration of some of the optical properties of a preferred diffraction surface 101 .
  • a beam of light 102 is directed to the diffraction surface 101.
  • the beam of light 102 is collimated (i.e. parallel) and 2o monochromatic or approximately monochromatic.
  • the diffraction surface 101 produces from the incident beam of light 102 a pair of conjugate diffracted optical beams 103a and 103b, and possibly other beams also.
  • the directions of the diffracted beams 103a and 103b relative to the incident beam 102 depend on the relative orientation of the incident • beam 102 and the diffraction surface 101 .
  • Each of the diffracted beams 103a and 103b has a specified Intensity Pattern (as defined above) resulting from a specified optically diffractive structure incorporated into the diffraction surface 101 .
  • the Intensity Patterns of the diffracted beams 103a and 103b are indicated by 104a and 104b respectively.
  • the Intensity Patterns 104a and 104b result from optically diffractive structure incorporated into the diffraction surface 30 101 either at the surface or at an internal interface.
  • the diffraction surface 101 is authenticated via machine recognition of one or more of the diffracted beam Intensity Patterns produced by the diffraction surface 101 .
  • one or both of the Intensity Patterns 104a and 104b must be machine recognisable and in order to provide secure authentication should preferably differ from 35 the Intensity Patterns produced by conventional diffractive surfaces.
  • the Intensity Patterns of diffracted beams produced by the preferred diffraction surfaces should therefore be other than a single peaked Intensity Pattern.
  • the diffracted beam Intensity Patterns produced by the preferred diffraction surfaces will have more than one Significant Optical Feature (as defined above).
  • a diffraction surface may produce diffracted beam Intensity Patterns in the form of a number of bright peaks or bright bands or in the form of bright lines which form one or more closed loops or in the form of other complex shapes and patterns. 5
  • the essential point is that the diffracted beam Intensity Patterns must be machine recognisable and must be different from the diffracted beam Intensity Patterns produced by conventional diffractive surfaces.
  • a diffraction surface may be designed to produce a different number of diffracted beams from that illustrated in figure 1 and that the different ⁇ o diffracted beams may have different Intensity Patterns.
  • the diffraction surface 101 may be designed such that the Intensity Pattern, and/or other properties such as direction, of a diffracted beam may vary as the region of the diffraction surface 101 illuminated by the optical beam 102 varies.
  • the Intensity Pattern 104a or 104b may change in a continuous or discontinuous manner in terms of size, shape, orientation or character to produce an "animation" effect which may add to the security provided through the use of the diffraction surface 101.
  • the diffractive properties of the diffraction surface 101 depend on the structure incorporated into the surface 101 .
  • the diffraction surface 101
  • the 20 includes a specified "groove” or “line” pattern either at the surface or internally.
  • Said grooves when viewed from above the surface 101 may be straight or curved and in general will have variable spacings in order to achieve the required diffracted beam Intensity Patterns.
  • the cross sectional shapes and depths of said grooves in the diffraction surface 101 may also be specified in order to determine the properties of 5 the diffracted beam Intensity Patterns such as the pattern shape or the intensity gradations within said patterns. In this case said grooves act as a so-called "phase grating" .
  • figure 2 is an illustration of a preferred embodiment of a diffraction surface along with the diffracted beam Intensity Pattern produced from said surface.
  • Figure 2(a) is an illustration of the diffraction surface 201 as viewed from above the surface.
  • the surface includes a number of lines or grooves 202 which are curved and have variable spacing across said surface 201 .
  • the diffraction surface 201 is designed to produce a number of diffracted beams, of the type described in relation to figure 1.
  • the pattern of the grooves 202 in the surface 201 is designed so as to produce diffracted 5 beams with specified Intensity Patterns which can be machine recognised in order to authenticate the diffraction surface 201 .
  • Figure 2(b) illustrates the type of diffracted beam Intensity Patterns produced by a surface of the type illustrated in figure 2(a) when illuminated by a single collimated monochromatic incident optical beam.
  • the optical intensity I of the diffracted light is plotted against position (X,Y) in the plane of the surface intercepting the diffracted light.
  • the contours in figure 2(b) are lines of constant optical intensity which therefore form an Intensity Pattern of the diffracted beams produced by a diffraction surface of the type illustrated in figure 2(a). It can be seen from figure 2(b) that in this case a number of distinct "ridges" occur in the Intensity Pattern.
  • the central peak 203 in figure 2(b) corresponds to specular reflection of the incident beam of light.
  • the diffracted beam Intensity Pattern illustrated in figure 2(b) can be machine recognised using an optical detector array as described herein. It should be appreciated, however, that the diffraction surface illustrated in figure 2(a) may be authenticated via machine recognition of only part of the overall, or total, diffracted beam Intensity Pattern ⁇ o illustrated in figure 2(b). For example, only one of the abovementioned "ridges" in the Intensity Pattern illustrated in figure 2(b) may be machine recognised during the authentication process.
  • Figure 3 is a schematic illustration of a preferred embodiment of a device 301 used in reading and authenticating a diffraction surface 302. Also illustrated in figure 3 is some i s of the electronics associated with operating the device 301.
  • Figure 3(a) illustrates the device 301 in side cutaway view, while figure 3(b) illustrates a front view of the device
  • the diffraction surface 302 is positioned by some means relative to the device 301.
  • the device 301 has an outer package 303.
  • the device 301 also has a front window 304
  • the window 304 may be made from a single piece of material or may be made up of several different pieces.
  • figure 3(b) illustrates a front view of part of the ' device 301 only. Specifically, figure 3(b) does not include the window 304 and also does ⁇ 25 not include the electronics associated with operation of the device 301 as shown in figure 3(a).
  • the device 301 includes a laser diode light source 305 which produces a beam of light 306.
  • the light beam 306 is usually an asymmetrically divergent light beam.
  • the section 304b of the window 304 is an optical lens arrangement designed to produce from 30 the light beam 306 a collimated (i.e. parallel) reading light beam 307.
  • the section 304b of the window 304 may be a single component lens or may consist of a number of lens components.
  • the reading light beam 307 is directed to the diffraction surface 302.
  • the diffraction surface 302 produces from the reading light beam 35 307 a conjugate pair of diffracted light beams 308a and 308b.
  • Other light beams may also be produced from the reading light beam 307 by the surface 302, but will not be considered in the present description.
  • the diffracted beams 308a and 308b will generally be divergent, although some diffraction surfaces may be designed to produce convergent beams 308a and 308b.
  • the diffracted beams produced by the diffraction surface 302 have characteristic and machine readable Intensity Patterns which patterns result from the diffractive structure incorporated into the diffraction surface 302.
  • the diffracted beam 308a passes through the section 304a of the window 304 and onto an optical sensor 309.
  • the section 304a of the window 304 should ideally cause no distortion of the beam 308a.
  • the section 304a of the window 304 is thin and planar and therefore does not significantly distort the beam 308a.
  • the optical sensor 309 is an array of separate optical detection regions 310 enabling a measurement of the optical Intensity Pattern 31 1 of the diffracted beam 308a at the optical sensor 309 in order to authenticate the diffraction surface 302.
  • the optical detector array 309 may be configured in one of a number of different ways.
  • the optical detector array 309 is made up of a number of optical detection regions 310 each of which measures incident optical intensity.
  • the optical detector array therefore enables a measurement of the Intensity Pattern of the diffracted beam 308a by measuring the optical intensity of the diffracted beam 308a at a number of different points corresponding to the optical detectors 10.
  • the optical detector array 309 provides electronic signals 312 at the output 313 which electronic signals 312 are representative of the outputs of the optical detectors 10 making up the optical detector array 309, and therefore representative of the optical Intensity Pattern of the beam 308a at the optical detector array 309.
  • the electronic signals 312 representing the Intensity Pattern of the beam 308a are compared with a specified set of values 314 in an electronic device 315.
  • the set of values 314 is stored in an electronic memory 316 and represents an authentic or "template” optical Intensity Pattern.
  • the electronic device 315 therefore compares the measured optical Intensity Pattern, as represented by the signals 312, with a "template” optical Intensity Pattern, as represented by the signals 314, in order to determine whether or not the measured optical Intensity Pattern matches the template to within reasonable error.
  • the comparison device 315 produces an output signal 317 at the output 318 to indicate whether or not the measured and template optical Intensity Patterns match, to within reasonable error.
  • the measured optical Intensity Pattern results from the diffractive structure incorporated into the diffraction surface 302.
  • the template Intensity Pattern corresponds to an authentic diffraction surface.
  • matching of the signals 312 representing the measured optical Intensity Pattern and the signals 314 representing the template optical Intensity Pattern is an indication that the diffraction surface 302 is authentic, whereas non- matching is an indication that the surface 302 is not authentic.
  • Each of the different diffraction surfaces has a corresponding "template” optical Intensity Pattern 314 to be stored in the memory device 316. Therefore each diffraction surface reader device will store template optical Intensity Pattern values 314 corresponding to the type or types of diffraction surface for which the reader is intended. It should be appreciated that a diffraction reader 301 may store more than one "template" optical Intensity Pattern, thereby enabling the reader to be 5 used with any of the corresponding types of the diffraction surface.
  • the diffracted beam 308b which in this preferred embodiment is conjugate to the diffracted beam 308a, passes through the section 304c of the window 304 and onto an optical sensor 319 which differs in design and function from the optical sensor 309.
  • the section 304c of the window 304 is an optical lens or combination of optical lenses which ⁇ o acts to image the area of the diffraction surface 302 illuminated by the reading beam 307 onto the surface of the optical sensor 319, thereby producing an image 320.
  • the image 320 formed at the optical sensor 3 19 may be magnified or minified relative to the illuminated area at the diffraction surface 302.
  • the image 320 produced at the optical sensor 3 19 will not be the diffracted beam Intensity Pattern, as is i s the case with the diffracted beam 308a and optical sensor 309, but will instead be an image of any pattern recorded in the diffraction surface 302.
  • the purpose of the optical sensor 319 is to read any information recorded as a pattern on or in the diffraction surface 302.
  • the optical sensor 3 19 includes one or more optical detection regions 32 1 each configured according to the type of pattern anticipated 0 at the optical sensor 3 19. More than one optical detection region 32 1 may be included on the optical sensor 319 since the position of the image 320 on the optical sensor 319 will depend on the relative orientation of the device 301 and the diffraction surface 302, and hence the inclusion of a number of optical detection regions 32 1 will help ensure that the image 320 is detected regardless of its position on the optical sensor 319.
  • each optical detection region 321 will preferably be a single optical detector which may have an active detection area shaped either as a spot or as a narrow slit (as illustrated in figure 3) parallel to the anticipated direction of the bars in the bar code image 320 formed at the optical sensor o 319, the diameter of said spot or the width of said slit geometry governing the resolution of the bar code reading operation at the optical sensor 319.
  • the diffraction surface 302 may have a two dimensional array of pixels recorded on or in it in some manner so as to represent information in a machine readable form, in which case each optical detection region 321 5 may preferably be a linear or two dimensional array of optical detector elements with the long axis of said array positioned parallel to the anticipated direction of one of the axes in the two dimensional array image 320 produced at the optical sensor 319.
  • the optical detection regions 321 produce electronic signals 322 at the output 323 which electronic signals 322 are representative of the optical signals at the optical detection regions 321.
  • the signals 322 may be made up of the outputs of the optical detectors 321 interleaved together.
  • the electronic ⁇ o signals 322 are fed to an electronic device 324 which processes the signals 322 to produce an output signal 325 at the output 326 which signal 325 is representative of the data read from the diffraction surface 302.
  • the electronic device 324 may select and process from the outputs of the optical detection regions 321 that output which has the greatest signal to noise ratio, i s
  • the position of the optical Intensity Pattern 31 1 of the diffracted beam 308a on the optical detector array 309 will vary depending on the relative orientation of the reading device 301 and diffraction surface 302. However, it is intended that authentication of the diffraction surface 302 via comparison of the Intensity Pattern 31 1 with a "template" Intensity Pattern stored in the memory device 316 be possible regardless of the position of 0 the Intensity Pattern 31 1 on the optical detector array 309, provided that the required diffracted beam Intensity Patterns do fall on the optical detector array 309.
  • the device 315 may be advantageous for the device 315 to be able to determine the timing of the portion of the ' signal 312 representing the Intensity Pattern 31 1. This can be achieved in one of a number . 5 of ways, for example in one preferred embodiment this could be achieved by deliberately including in the optical Intensity Pattern 31 1 an optical feature which acts as a "start" signal for the electronic comparison device 315.
  • optical detection elements 310 are arranged in a Cartesian layout i.e. square or rectangular.
  • the optical detection elements 310 could instead be arranged in a different manner.
  • the optical detection elements 310 could be arranged in a radial/circumferential layout. 5
  • a simplified version of the device shown in figure 3 could be used, where said simplified device would not include the optical sensor 319 or the electronic device 324, and where the remaining components may in some embodiments be re-arranged while still performing similar functions.
  • the optical detection regions 321 may be overlaid with masks in order to achieve the appropriate active optical detection area and spatial filtering of the incident optical beam. Measurement and comparison of the optical Intensity Pattern 31 1 of the diffracted beam 308a may not be required at all points on the diffraction surface 302 in order to authenticate the surface 302. Instead, confirmation of the Intensity Pattern 31 1 of the diffracted beam 308a may only be required at a predetermined number (or more) of points or at a number of predetermined locations on the diffraction surface 302 in order to authenticate the diffraction surface 302.
  • the laser diode 305 may be pulsed between lower and upper power output levels at an appropriate repetition rate and with an appropriate duty cycle to obtain the required "snapshots" of the Intensity Pattern 31 1 from the optical detector array 309.
  • Pulsing the laser diode 305 has the advantage of reducing the thermal energy generated by the laser diode and hence reducing the heat dissipation requirement for the reader device. Pulsing of the laser diode, if carried out, would need to be done under conditions which do not impede reading by the optical sensor 319 of information recorded in the diffraction surface 302. In another preferred embodiment, said "snapshots" could be obtained by electronically “shuttering" the optical ' detector array 309.
  • the device 301 as illustrated in figure 3 uses a single light source to generate a single optical reading beam 307 directed to the diffraction surface 302.
  • each optical reading beam produces a pair of diffracted beams 308a and 308b as illustrated in figure 3.
  • Said multiple optical reading beams could be directed all to the same point or to different points on the diffraction surface 302 and may be incident on the diffraction surface at the same or different angles.
  • a number of optical reading beams all of the same wavelength, generated by one or more optical sources, may be incident on the same region of the diffraction surface 302 from different directions.
  • An advantage of using multiple optical reading beams in this manner is that multiple diffracted beams will be produced in different directions, one of type 308a and one of type 308b for each incident optical reading beam, thereby increasing the probability that for a given relative orientation of the device 301 and diffraction surface 302 at least one diffracted beam of the type 308a and at least one diffracted beam of the type 308b will fall on the optical sensors 309 and 319 respectively thereby enabling the reader device to operate over a greater range of relative orientations of the device 301 and diffraction surface 302.
  • the diffraction surface 302 illustrated in figure 3 produces only a single pair of conjugate diffracted beams - namely the beams 308a and 308b. It should be appreciated that other diffraction surfaces may be designed to produce more than these two diffracted beams and consequently that more than one diffracted beam Intensity Pattern 31 1 may occur at the optical detector array 309. Authentication of such a diffraction surface may require confirmation (via the comparison device 315 as described herein) of only one of said diffracted beam Intensity Patterns at the optical detector array 309, or may instead require confirmation of a number of said diffracted beam Intensity Patterns at the optical detector array 309.
  • the memory device 316 will be required to store "template” Intensity Patterns for those optical Intensity Patterns which require confirmation, which may mean that the memory device 316 must be capable of storing more than one "template” Intensity Pattern.

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  • Credit Cards Or The Like (AREA)
  • Inspection Of Paper Currency And Valuable Securities (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

Procédé et appareil (301) permettant de détecter des données mémorisées sur une surface de diffraction (101) d'une mémoire optique. Un faisceau lumineux de lecture (102) éclaire la surface (101). Au moins un faisceau lumineux diffracté (104) est produit, lequel présente un diagramme d'intensité prédéterminé. Un détecteur (309) est éclairé par un faisceau diffracté (308) et est utilisé à des fins d'authentification. Un second détecteur (319) est éclairé par un second faisceau diffracté (308), lequel passe à travers une lentille optique (lentille de formation d'image) (304) afin qu'une image sont produite sur le détecteur (319). Le détecteur (309) produit un signal à des fins d'authentification, ce signal pouvant être comparé à un signal 'gabarit'. Le signal généré par le détecteur (319) comprend des informations supplémentaires à celles contenues dans le signal produit par le détecteur (309).
EP93918801A 1992-09-07 1993-09-06 Detecteur de donnees a surface de diffraction. Ceased EP0660959A4 (fr)

Applications Claiming Priority (22)

Application Number Priority Date Filing Date Title
AUPL451292 1992-09-07
AUPL4512/92 1992-09-07
AUPL681793 1993-01-18
AUPL6817/93 1993-01-18
AUPL701293 1993-01-29
AUPL7012/93 1993-01-29
AUPL7217/93 1993-02-11
AUPL721793 1993-02-11
AUPL7259/93 1993-02-15
AUPL725993 1993-02-15
AUPL7789/93 1993-03-15
AUPL778993 1993-03-15
JP018157U JPH0670558U (ja) 1993-03-19 1993-03-19 観賞魚用濾過装置
AUPL8454/93 1993-04-27
AUPL845493 1993-04-27
AUPL915093 1993-06-02
AUPL9150/93 1993-06-02
AUPL9273/93 1993-06-09
AUPL927393 1993-06-09
AUPL958893 1993-06-24
AUPL9588/93 1993-06-24
PCT/AU1993/000455 WO1994006097A1 (fr) 1992-09-07 1993-09-06 Detecteur de donnees a surface de diffraction

Publications (2)

Publication Number Publication Date
EP0660959A1 true EP0660959A1 (fr) 1995-07-05
EP0660959A4 EP0660959A4 (fr) 1998-05-06

Family

ID=27581378

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93918801A Ceased EP0660959A4 (fr) 1992-09-07 1993-09-06 Detecteur de donnees a surface de diffraction.

Country Status (4)

Country Link
EP (1) EP0660959A4 (fr)
JP (1) JPH08501646A (fr)
CA (1) CA2143952A1 (fr)
WO (1) WO1994006097A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1995012860A1 (fr) * 1993-11-05 1995-05-11 Mikoh Technology Limited Dispositif de visualisation par diffraction
US5717092A (en) * 1996-03-29 1998-02-10 Vertex Pharmaceuticals Inc. Compounds with improved multi-drug resistance activity
DE10345898A1 (de) 2003-07-11 2005-01-27 Tesa Scribos Gmbh Verfahren zum Berechnen und zum Erzeugen eines computergenerierten Hologramms sowie ein Speichermedium mit einem computergenerierten Hologramm und eine Lesevorrichtung
DE102004018856A1 (de) * 2004-04-19 2005-11-03 Giesecke & Devrient Gmbh Vorrichtung zur Prüfung von Banknoten
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Also Published As

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WO1994006097A1 (fr) 1994-03-17
JPH08501646A (ja) 1996-02-20
CA2143952A1 (fr) 1994-03-17
EP0660959A4 (fr) 1998-05-06

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