|Publication number||US3829661 A|
|Publication date||Aug 13, 1974|
|Filing date||Jul 18, 1972|
|Priority date||Sep 21, 1970|
|Publication number||US 3829661 A, US 3829661A, US-A-3829661, US3829661 A, US3829661A|
|Inventors||Johnson E, Silverman D|
|Original Assignee||Johnson E, Silverman D|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (33), Classifications (22)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Birmingham Ave., Tulsa, Okla. 74105; Everett A. Johnson, 15 S. Prospect Ave., Park Ridge, 111.
2'2? "I255 vase? GR 1 29 6911. 1 I
United States Patent 1191 1111 3,829,661 Silverman et a1. 1451 'Aug. 13, 1974 [5 iq Q1358 CONTROL SYSTEM 3,588,440 6/1971 Morse 331/945 A  Inventors: Daniel Sherman 5969 S. 3,257,255) 4/1972 Rothrock... 331/945 A 7/1972 Johnson 235/617 B Primary ExaminerDaryl W. Cook Assistant Examiner-Robert M. Kilgore  Filed: July 18, 1972 I 57] ABSTRACT  App]. N0.: 272,739 This invention describes a system for access control wherein a control card is presented to a control F w? Apphcanon Data means. If the control card is authenticated, then ac-  conmuanomngpay "2 74966 Septcess is gained. If it is not authenticated, access is not 1970 gained, the control card is retained, and an alarm may 52 us. Cl.235/61.7 B, 235/61.12 R, 235/61.1l E, be sounded 40/22, 355/41 The control card contains at least two means; (1)  Int CLW G06k 1/16 606k 19/02, G06b 7 /04 machine readable indicia identifying the card, and (2) (306k 7/10 ogf 3/02 a random pattern of micro spots, which pattern is  Field of Search. 235/61.7 B, 61.11 E, 61.11 D, derlved (by dlrect Copymg Such as by fqcussed 235/ 112 11 ;355/41 42;331/494 5 laser beam) from one 01" a plurality of dlfferent A; 194/4; 40/22; 250/219 DC patterns, retained in a bank of such micro patterns, each such micro pattern identified by, and selectable  References Cited in accordance with, different unique indicia, identical UNITED STATES PATENTS with the machine readable indicia on said cards. 3 039 582 6,1962 Simian 194/4 In use the control card is introduced into the control 3 267 800 8/1966 Bailiod.1111: 11::::::. 355/42 means and the indicia are read- Master micro P 3:325:81) 6/1967 Fraser 250/219 DC Corresponding to the indicia is Selected from the bank- 3.351,948 11/1967 Bonn..... 331/945 A The card micro pattern and master micro pattern are 3,364,087 1/1968 Soloman 331/945 A compared. If the comparison okay, the card is 3,410,979 11/1968 Larsson 331/945 A authenticated 3,492,072 1/1970 Haun 331/945 A 3,571,957 3/1971 Cumming 40/22 13 Clalms, 3 Drawing Flgures ACCESS OPER I BANK CONTROL'I 90 I 75 I /a I's/ZE SENSOR I 79 78 77 COMPARISON we 82 I 87 SENSOR 84 |f-72 76 I 83 I II) 1 14 1/ 7 7 104 1 v I U 0 K 20/ OPT! S 86 [06 THIRD STATION ACCESS CONTROL SYSTEM CROSS REFERENCE TO RELATED APPLICATION This application is a continuation in part of our copending application Ser. No. 74,066; filed Sept. 21, I970; entitled: Method and Apparatus for Authentication of Information Records now US. Pat. No. 3,677,465. Related copending applications are Ser. No. 262,290, filed by one of us June 13, I972, entitled Method and Apparatus for Preparing Master and Facsimile Digital Spot Records, and our joint application Ser. No. 272,686, filed July 17, 1972, and entitled Method and Apparatus for Authentication of Information Records.
BACKGROUND OF THE INVENTION This invention is in the field of control cards for gaining access. More particularly it is for gaining access to a restricted area, or access to restricted material or papers, or access to money, tickets, checks and the like.
In the prior art there have been many types of control cards described. All of these attempt, in one way or another, to provide some crucial test, which can be performed on the card so as to determine whether it is authentic, or a copy or forgery. All of the physical properties of the prior art cards were capable of being copied, and therefore the tests of validity or authentication were of little value.
SUMMARY OF THE INVENTION It is a principle object of this invention to provide an access control system which is selective and which is extremely difficult or impossible to duplicate.
It is a further object of this invention to provide an access control system which is self protective in that it has plural means to detect forgeries.
These and other objects are realized and the limitations of the prior art devices are overcome in this invention, in which the authentication is obtained by precise comparison of a random spot pattern with an identical one, from which the first one was derived. The spots in the pattern are microspots, too small to be seen with the naked eye, and recorded in a suitable sheet material by copying through microperforations in a master micro pattern, by means of a focussed laser beam.
Because of the extremely small size of the spots, the pattern can not be copied by a stop-position-print sys tem.
Furthermore the sheet material must have a thickness and melting point such that it will withstand, without melting. the passage of a focussed laser beam of a selected intensity.
The pattern can not be copied photographically, since the photographic material will not withstand the laser beam.
The pattern can not be copied photographically and etched, since the microperforations will not be of the correct size.
They can only be copied from the mater pattern by passage of a focussed laser beam over the mieroperfo= rations in the master pattern card.
In the use of the control card, it is inserted into eon= trol unit.
It is then advanced to a first station where the indicia are read. At this point the indicia are compared to a prior list of indicia which are indicated as unacceptable. If the indicia are okay it then goes to the second station.
At the Second Station the card is scanned by a focussed laser beam of a specified intensity level. This level is just below the level which will burn the'pattern sheet of the valid cards. If the pattern sheet of the card is not burned, as evidenced by a photoelectric system for detecting major perforations in the pattern sheet, the card then goes to the third station.
At the Third Station the micro pattern on the card is compared to a selected master pattern which corresponds to, and has been selected from a bank of master patterns in accordance with the indicia read from the card.
Two tests are made at this station. The first is to compare the pattern on the card with the master pattern. If this checks, then the second test is made.
In the second test, the sizes of the microperforations in the pattern sheet are compared to the size of the microperforations in the master card. This can be done by slowly shifting the position of one pattern with respect to the other, at a selected constant speed, and measuring the time that light passes through any selected spot, as plurality of spots.
If the card passes this test, then it is considered authentic and the appropriate operative mechanism is activated to provide the access requested. Also the card is returned to the owner who first inserted into the control apparatus.
Not all of these tests may be required. The principal test, is of course, the comparison of the patterns in station 3 test (a), the master pattern having been selected on the basis of indicia read in the First Station. Also, other tests may be provided, including, for example, comparing a photograph on the card with the person presenting the card, or comparing finger prints, etc.
BRIEF DESCRIPTION OF THE DRAWINGS These and other objects of this invention and a better understanding of the principles and details of the invention will be evident from the following description taken in conjunction with the appended drawings, in which:
FIG. 1 illustrates a type of access card useful in this system.
FIG. 2 illustrates the preferred embodiment of the access system of this invention.
FIG. 3 illustrates the test for perforation size.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, numeral 10 indicates generally the card input station, numeral 12 indicates generally the First Station, numeral 14 indicates computer apparatus to check the indicia against a prepared list of indicia, numeral 16 indicates the Second Station, numeral 18 the Third Station, 20 indicates the pattern comparison means, 22 the operative means responsive to the validation means, 24 the perforation size measurement means, 26 the access control card, 28 the machine readable indicia on the control card, and 30 the pattern of microperforations by means of which the control card will be validated or authenticated.
This application is a continuation in part of our copending application, Ser. No. 74,066, filed Sept. 21, 1970, entitled; Method and Apparatus for Authentication of Information Records, now U.S. Pat. No. 3,677,465, which is made part of this application, by reference, and will be'depended on for much of the detail of the apparatus to be described.
Also, there will only be schematic diagrams given of the physical apparatus, such as the case, the card handling means, and the operative means which actually accomplishes the access. This invention does not involve any specific means for housing the electronic and photo apparatus, or the card handling apparatus, and since there are a number of such devices discribed in the patent literature, such as for example U.S. Pats. Nos. 3,571,957, issued Mar. 23, 1971, No. 3,620,590 issued Nov. 16, 1971, No. 3,629,834, issued Dec. 21, 1971, and others, it is not deemed necessary to describe the details of construction or operation, since those are well known to one skilled in the art.
FIG. 1 indicates a card, token, sheet, web or other medium for carrying the specific information required in this invention. For convience, we will call this means a card, although, as is well known it can be in any one of many different forms.
There are two principal areas of the access control card, or access card, or control card, or simply card 40, that carry important information. The first space 28 carries indicia which are machine readable. These can be perforations, or embossed characters representing specific information, such as account number or name and address of the card owner, or other information. The group of characters 100, and spaces 102 that make up the indicia represent specific information. The words indicia, or characters, will represent the physical markings on the card, or the specific information they uniquely represent. The indicia on each card issued are all different, and associated with each indicia there is a different unique pattern, which is marked on the card in a second area 30.
The pattern 30 is made up of a random distribution of a plurality of spots, which are microperforations in a thin opaque metal layer. As described in our copending U.S. Pat. No. 3,677,465 the material 98 which carries the pattern 30 can be a thin evaporated layer of metal or a transparent base material such as clear plastic.
For each card carrying its unique pattern 94 there is an identical master pattern of microperforations in a metal layer. This master pattern can be a self supporting metal sheet or film, or a thin metal coating on a transparent plastic base, etc. The microperforations are preferably prepared in the master pattern by means of a pulsed focussed beam of laser radiation of a selected level L1 of intensity.
The patterns 94 in the sheets 98 are precise copies of the master patterns made by superimposing the master pattern material on top of the card material 98, and passing a continuous beam of focussed laser energy through the microperforations in the master pattern, to the underlying metal layer of the sheet 98, and burning microperforations in the same pattern as in the master pattern.
As explained in U.S. Pat. No. 3,677,465, it is necessary that the metal layer of the master pattern be of higher melting point, and/or thicker, than the metal layer of the sheet 98 of the card. Thus, when the intensity of the continuous focussed beam is set at a value of intensity level L2 where L2 is less than Ll, this beam will not affect the metal of the master pattern, but will burn holes in the sheet 98.
There is also a third intensity level L3, where L3 is less than L2, which when scanned across the material 98 will not affect the metal layer of the material 98.
On the record card 40 there may be other areas 95, 96, 97, etc. Which may include the signature of the card owner, his picture, or his fingerprint, or other identifying information, which can be further used to authenticate the card and the bearer of the card. Such additional information is well known in the art and forms no part of this invention, and will not be described further.
Referring now to FIG. 2, the card of FIG. 1 is inserted into an opening 32 in a casing 34 that houses a plurality of test or measuring stations. As mentioned above, the particular housing, or means of transport of the card, etc., form no part of this invention and reference is made to the prior art for such details.
The card entered at 32 is transported through passage 36 by means 38, well known in the art, to the First Station 12. Here the card 40 is presented with means 42, well known in the art, for reading the markings 28, and determining the information corresponding to the indicia. This information is sent to a computer means 46, which when it receives the indicia read from the card compares the indicia with a preselected list, bank or tape of indicia, to see if that specific information is listed in the bank or on the tape.
This list could be, for example, all indicia on cards lost, stolen, or otherwise declared invalid. If the specific indicia 93 is found on that list, the card is rejected and falls into a receptacle inside the housing (not shown). if desired, an appropriate notice is given to the person who inserted the card, that it is invalid and is being confiscated. At the same time the indicia read by 42 also goes by line 48 to the Third Station, for a purpose to be described later.
If the indicia read by 42 is not on the list at 46, then the card 40 progresses to the Second Station 16. Here two tests are performed. The first test is to check the nature of the material of the sheet 98. A laser 52 passes light through an intensity control means 54, via beam 56 to a mirror 58 and through an optical means 60 to focus the beam 62 onto the top surface of the material 98. The intensity level is adjusted to the level L3, which is just below the level L2, where it will burn the metal layer. With thelevel at L3, the beam is scanned across the pattern 30, in accordance with arrows 61.
If the material of the sheet 98 is not the proper material, for example, if it is a photographic emulsion, then it will not support the beam of intensity level L3, and parts or all of the opaque material 98 will be burned away. When this happens, as the beam is scanned in accordance with the arrows 61, openings in the opaque layer will be formed.
The second test is then applied. This involves passing light from a source 64 through lens 66, through the pattern area 30 and to a photoelectric sensor 70. If no light passes, it indicates that the material 98 is satisfactory. If light passes, it indicates that the material 98 is a substitute material, and therefore the card is invalid, and it is confiscated.
If the card 40 passes the tests at Station 2, it then goes to Station 3. Here there is a bank of master patterns.
These may be on separate cards or sheets, or may conveniently be on a reel or strip of material 76, with separate frames or areas, each having its unique pattern of microperforations in the metal layer of the strip. Corresponding to each frame, is an index, which corresponds to the indicia of that pattern. Thus, when the First Station reads the indicia, this information goes to control means 74. This control means operates motors 77, 82, which drive reels 78, 81 respectively to position the proper frame, and pattern in an aperture between the rollers 83, 84. Thus the correct master pattern corresponding to the indicia on the card is now displayed in the aperture 87. The control means 74 can be conventional, similar to the many examples of strip films or tapes carrying micropatterns and digital indicia, with means to transport the strip until a desired index is reached, etc.
The card 40 is now sent to the Third Station and positioned so that the pattern 94 is precisely lined up in the aperture 87 so that the two patterns, that is, the master pattern and the card pattern 30, are aligned. Optical means 86, cooperating with sensor means 88 determine if the patterns are identical. If they are not identical, the card 40 is discarded.
The materials of the master pattern and the card pat- I tern are specialized, in that the master material (metal) is of high melting temperature and/or thicker, while the card material (metal) is lower melting temperature and/or thinner. The patterns of microperforations are copied and burned into the card metal by focussed laser beam from the master material. The microperforations in both materials are of exceedingly small size, so that the patterns must be precisely positioned with respect to each other. Reference is made to US. Pat. 3,677,465 for details on the systems for comparing the two micropatterns. Normal digital reading systems are not practicable since the spots are too'small, and the spacings are random. Misalignment of one microperforation by a distance of the order of the diameter, (which may be as small as 0.0005 in.) will cause the comparison means 74 to reject the card.
The purpose of the use of thin metal layers and microperforations, and the transfer of patterns described, is to prevent forged copies from being used. For example, the simplest way to copy the pattern on a card is to make a photographic copy, and that copy (except for changes in dimension) might be used in the comparator 74. However, such a photographic copy will not stand the test of the laser of intensity L3. The only material that wil satisfy that test is a metal of the same melting point and thickness as the material 98 used in the card. And the pattern cannot be transferred from the card to the new material by photography. Nor can it be transferred by laser, since the laser of intensity level L2 which would burn microperforations in the new material would also destroy the card material.
However, the pattern could be etched in a suitable metal by photoetching. However, the size of the perforations would not duplicate those of the master card, and this is the reason for the next test.
In FIG. 2 the card 40 is shown connected to motor 104 by means 106. When the motor 104 is started the card will pass at a constant velocity past the master pattern on the strip. In FIG. 3 we have shown (enlarged) the relationship between a microperforation 110 on the master pattern as the corresponding microperforation 112 in the card passes to the right, in the direction of arrow 120. When the two are tangent at 114, light is just beginning to pass through the two microperforations. Consider for simplicity, that the opening is moving to the left. When the leading edge of 110 gets to position 115, the two microperforations are completely superimposed. Then when it gets to 116, there is no more light passing. Thus the two patterns must be relatively traversed by a distance from 1 14 to 116, equal to the sum of their diameters.
Now, consider that the card pattern has at least one perforation 122 that is oversize. Then the traverse must be over a distance from 114 to 118, (again the sum of their diameters) which will be larger than the distance 114 to 116. There are well known techniques for measuring small distances, such as measuring time of tranverse, etc., this would be done in means 92. Thus it will not be necessary to provide more details since the specific means forms no part of this invention.
if. the pattern comparison is okay and the test of size is okay, then the card will have passed all tests, and the card is validated and the operative means 22 is energized to provide the requested access. No detail is provided for the mechanism 22, which can be as simple as a relay to open a locked gate, or as complicated as a device for dispensing currency, providing access to a computer or to a cable TV circuit, credit purchase, etc., since these specific means form no part of this invention and are well know in the art.
While we have indicated means to check the validation of the pattern, and have indicated other means to test the authenticity of the card itself, it will be clear that the apparatus can be operated without carrying out all of the tests.
lt will be clear also, that while we call the patterns or the strip 76 the master patterns," these can be copies of other master patterns in materials of still greater thickness and/or higher melting point.
ln the drawing, FIG. 2 illustrates the system as a plurality of successive stations or operations on the control card. The area of the card devoted to indicia is separate from the area devoted to micropattern, and it is clear that the means to read and the means to compare may be situated within the outer boundary of the card. Thus the card need only be positioned in a single location.
Our disclosed invention includes an access control system for selectively controlling access on presentation and authentication of a control card. This card comprises card means, machine readable indicia carried thereby, and unique coded micropattern means thereon. The card authentication means comprises means to read the indicia, and a bank of authenticating master coded micropatterns. Selecting means, responsive to the means to read the indicia, selects the master coded micropattern from the bank corresponding to the coded micropattern on the card means; and means to compare the coded micropatterns on said card means with the master authentication micropattern selected from the bank in response to the read indicia.
The system may further include operative means responsive to said comparison means, said operative means including means to authorize access when the compared patterns correspond. -A preferred form includes coded micropattern means comprising an array of microperforations; and the coded micropattern means may include redundant coded patterns.
The system as described above in which said card micropattern is transferred from said master micropattern by focussed laser means of intensity level L2; and including means to scan across said card micropattern with a focussed laser beam of intensity level L3, where L3 is less than L2.
The microperforations may be burned in said master pattern in a metal layer of first melting point and first thickness by scanning with a focussed laser beam of intensity level LO through microperforations in a supermaster pattern in a third metal layer of third melting point and third thickness, where L is higher than L2.
' Also the system includes means, responsive to said means to read said indicia, to compare said indicia with a preselected list of indicia; and the master micropattern is in a first metal layer of first melting point and first thickness, and said card micropattern is in a second metal layer of second melting point and second thickness, and said first melting point may be higher than said second melting point and said first thickness may be greater than said second thickness.
The system includes means to compare the sizes of the microperforations in said card micropattern with the sizes of the microperforations in the master pattern.
While the invention has been described with a certain degree of particularity it is manifest that many changes may be made in the details of construction of the arrangement of components. It is understood that the invention is not to be limited to the specific embodiments set forth herein by way of exemplifying the invention, but the invention is to be limited only by the scope of the attached claim or claims, including the full range and equivalency to which each element or step thereof is entitled.
1. In an access control system for selectively controlling access on presentation and authentication of a control card, said control card comprising:
1. card means,
2. an unique coded micro pattern on said card means,
3. machine readable indicia carried by said card means, said indicia corresponding to the unique coded micro pattern on said card means, the improvement in apparatus for authentication of said control card comprising:
1. means to read said indicia on said control card,
2. a bank of unique authenticating master coded micro patterns and of indicia, each of said indicia being associated with one of said coded micro patterns,
3. means responsive to said means to read said indicia to select the authenticating master coded micro pattern from said bank corresponding to said indicia and to the coded micro pattern on said control card; and 4. means responsive to said means to select to compare said coded micro pattern on said control card with the authenticating master coded micro pattern selected from said bank. 2. The system as in claim 1 including operative means responsive to said comparison means. 7 v
3. The system as in claim 2 in which said operative means comprises means to authorize access when the compared patterns correspond.
4. The system as in claim 1 in which the coded micropattern means includes redundant coded patterns.
5. The system as in claim 1 in which the master micropattern is in a first metal layer of first melting point and first thickness, and said card micropattern is in a second metal layer of second melting point and second thickness.
6. The system as in claim 1 in which said first melting point is higher than said second melting point.
7. The system as in claim 5 in which said first thickness is greater than said second thickness.
8. The system as in claim 1 in which said card micropattern is transferred from said master micropattern by focussed laser means of intensity level L2.
9. The system as in claim 1 including means responsive to said means to read said indicia to compare said indicia with a preselected list of indicia.
10. The system as in claim 8 including means to scan across said card micropattern with a focussed laser beam of intensity level L3, where L3 is less than L2.
1 1. The system as in claim 1 including means to compare the sizes of the microperforations in said card micropattern with the sizes of the microperforations in said master pattern.
12. The system as in claim 1 in which said microperforations are burned in said master pattern in a metal layer of first melting point and a first thickness by scanning with a focussed laser beam of intensity level LO through microperforations in a supermaster pattern in a third metal layer of third melting point and third thickness, where L0 is higher than L2.
13. In an access control system in accordance with claim 1 wherein the unique coded micropatterns on said control card and in said bank comprise microperforations produced by a focused laser beam, and the patterns on a card and selected from the bank by corresponding indicia are compared by means of a focused laser beam.
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3999042 *||Aug 8, 1974||Dec 21, 1976||Daniel Silverman||Access control system|
|US4025759 *||Oct 16, 1975||May 24, 1977||The Grey Lab. Establishment||Checking apparatus for documents|
|US4072929 *||Feb 23, 1976||Feb 7, 1978||George Edwin Wolfe||Computer controlled bulk storage fluid dispensing terminal|
|US4094462 *||Aug 2, 1976||Jun 13, 1978||Ncr Corporation||Method and means for providing and testing secure identification data|
|US4103150 *||Mar 5, 1976||Jul 25, 1978||Guhl & Scheibler Ag||Arrangement for controlling the access to an establishment and entry card suitable for such an arrangement|
|US4150781 *||Dec 21, 1976||Apr 24, 1979||Johnson Everett A||Access authentication system|
|US4213038 *||Dec 20, 1976||Jul 15, 1980||Johnson Everett A||Access security system|
|US4303852 *||Apr 23, 1979||Dec 1, 1981||Daniel Silverman||Access security control|
|US4441807 *||Feb 17, 1982||Apr 10, 1984||Lucht Engineering, Inc.||Photographic printing system including an improved masking card|
|US4472050 *||Jan 3, 1984||Sep 18, 1984||Lutz H. Prufer||Copying apparatus for producing combined copies|
|US4533237 *||Jul 9, 1984||Aug 6, 1985||Stockburger H||Method and device for registering the use of copying machines|
|US4544184 *||Jul 7, 1983||Oct 1, 1985||Freund Precision, Inc.||Tamper-proof identification card and identification system|
|US4649265 *||Mar 4, 1985||Mar 10, 1987||Copytex Gmbh Sicherheitssysteme||Method for protection against the re-transfer of uniquely recorded information on a data carrier and apparatus for recording and/or reading re-transfer-protected information|
|US4814589 *||Apr 18, 1986||Mar 21, 1989||Leonard Storch||Information transfer and use, particularly with respect to objects such as gambling chips|
|US5023527 *||Apr 18, 1990||Jun 11, 1991||General Electric Company||Control circuits, electronically commutated motor systems and methods|
|US5208630 *||Nov 4, 1991||May 4, 1993||Xerox Corporation||Process for the authentication of documents utilizing encapsulated toners|
|US5283422 *||Aug 10, 1992||Feb 1, 1994||Cias, Inc.||Information transfer and use, particularly with respect to counterfeit detection|
|US5367148 *||Mar 15, 1991||Nov 22, 1994||Cias, Inc.||Counterfeit detection using ID numbers with at least one random portion|
|US5396559 *||Aug 24, 1990||Mar 7, 1995||Mcgrew; Stephen P.||Anticounterfeiting method and device utilizing holograms and pseudorandom dot patterns|
|US5430277 *||Sep 21, 1993||Jul 4, 1995||Kabushiki Kaisha Toshiba||Image recording medium, a processing apparatus thereof, and an entrance/exit control system using the image recording medium|
|US6532297||Jul 14, 1998||Mar 11, 2003||Digital Biometrics, Inc.||Gambling chip recognition system|
|US6848049 *||Jun 10, 1998||Jan 25, 2005||Stmicroelectronics S.A.||Method and apparatus for the authentication of integrated circuits|
|US7687271||Apr 22, 2004||Mar 30, 2010||Kodak Graphic Communications Canada Company||Covert authentication method and apparatus|
|US20030174864 *||Mar 10, 2003||Sep 18, 2003||Digital Biometrics, Inc.||Gambling chip recognition system|
|US20050164781 *||Mar 4, 2005||Jul 28, 2005||Thomas Lindquist||Gambling chip recognition system|
|US20050239207 *||Apr 22, 2004||Oct 27, 2005||Daniel Gelbart||Covert authentication method and apparatus|
|US20050282622 *||May 23, 2005||Dec 22, 2005||Shuffle Master, Inc.||Gambling chip recognition system|
|DE2542802A1 *||Sep 25, 1975||Apr 15, 1976||Grey Lab Establishment||Pruefgeraet fuer urkunden|
|DE2560672C2 *||Sep 25, 1975||Oct 12, 1989||Gao Gesellschaft Fuer Automation Und Organisation Mbh, 8000 Muenchen, De||Title not available|
|EP0238415A2 *||Mar 18, 1987||Sep 23, 1987||Jean-Albert Despres||Object identifying device|
|EP0238415A3 *||Mar 18, 1987||Jul 20, 1988||Jean-Albert Despres||Object identifying device|
|EP0290021A2 *||May 5, 1988||Nov 9, 1988||Estee Lauder Inc.||System and method for encoding objects|
|EP0290021A3 *||May 5, 1988||Sep 20, 1989||Estee Lauder Inc.||System and method for encoding objects|
|U.S. Classification||235/382, 235/487, 355/41, 283/73|
|International Classification||G07F7/12, G06K19/14, G07F7/08, G07C9/00, B44F1/12, B44F1/00|
|Cooperative Classification||G06K19/14, G07F7/12, G07F7/08, G07C9/00007, G06Q20/347, G07F7/086|
|European Classification||G06Q20/347, G07F7/12, G07C9/00B, G07F7/08B, G06K19/14, G07F7/08|