Patent EP0304194A2 successfully refreshed from Google Patents.
EP0304194A2
Expired / Lapsed
EP
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Data carriers
Assignee: Chubb Electronics Ltd
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Filing: 1988-08-03
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Granted: —
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Expires: 2008-08-03
Abstract
Abstract A carrier (1,101) bears data in the form of one or more holographic optical elements (HOEs) (4,104) representing e.g. identification data on an access-control card or authentication data for documents or goods. In Fig 1, each HOE (4) is adapted to couple into the structure of the carrier light directed at a selected angle from an emitter (9) in a reading apparatus and to direct that light within the carrier at an angle such that it is transmitted through the carrier by a process involving total internal reflection at an exposed surface thereof. The light can therefore be coupled out of the carrier at a location spaced from the HOE (4) through an element (11) of selected refractive index placed into contact with the surface of the carrier, and sensed by an associated detector (12). Alternatively in Fig 7 there is a light path from an emitter (110) coupling light into the carrier through an element (111) of selected refractive index, with the light being transmitted by total internal reflection to a HOE (104) which couples it out to a detector (112). In either case, detection of light from one location on the carrier when it is illuminated at another location therefore signals the presence of the HOE (4,104) which otherwise remains completely invisible. The presence or absence of HOEs at specified positions along a track or in other forms of array can therefore be used to represent data bits, to be detected along parallel tracks or at different array positions by virtue of the light transmission through the carrier, making fraudulent reproduction or imitation of the data very difficult.
Inventors
- 👤 Kenneth John Drinkwater
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 22:43
CPC Classifications
G; G06; G06K; G06K19/00; G06K19/06; G06K19/06009; G06K19/08; G06K19/10; G06K19/16
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
155 words
A data carrier (1) bearing at least one holographic optical element (HOE) (4) at a (respective) first location, characterised in that the or each said HOE (4) is adapted to couple into the structure of the data carrier (1) light of a selected wavelength which is incident thereto from a selected direction (6); and the data carrier (1) is constructed such as to trap the light coupled by the or each said HOE (4) and transmit the same (7) through the structure of the data carrier (1) to one or more respective second locations spaced from the first location(s), by a process involving total internal reflection of such light (7) at an exposed surface of the data carrier (1); whereby the transmitted light (7) can be coupled out of the structure of the data carrier (1) by placing an element (11) of selected refractive index into contact with said exposed surface at said second location(s).
Claim 2
Dependent Claim
155 words
A data carrier (1) bearing at least one holographic optical element (HOE) (4) at a (respective) first location, characterised in that the or each said HOE (4) is adapted to couple into the structure of the data carrier (1) light of a selected wavelength which is incident thereto from a selected direction (6); and the data carrier (1) is constructed such as to trap the light coupled by the or each said HOE (4) and transmit the same (7) through the structure of the data carrier (1) to one or more respective second locations spaced from the first location(s), by a process involving total internal reflection of such light (7) at an exposed surface of the data carrier (1); whereby the transmitted light (7) can be coupled out of the structure of the data carrier (1) by placing an element (11) of selected refractive index into contact with said exposed surface at said second location(s).
Claim 3
Dependent Claim
39 words
A data carrier (1) according to claim 1 constructed such as to transmit the light (7) trapped as aforesaid to said location(s) by a process involving total internal reflection of such light (7) at two opposite exposed surfaces thereof.
Claim 4
Dependent Claim
65 words
A data carrier (1) according to claim 1 constructed such as to transmit the light (7) trapped as aforesaid to said second location(s) by a process involving total internal reflection of such light (7) at said exposed surface and reflection of such light (7) at a specular reflective surface (8) provided within the structure of the data carrier (1) in parallel with said exposed surface.
Claim 5
Dependent Claim
78 words
A data carrier (1) according to any preceding claim comprising a plurality of said HOEs (4) disposed in a coded track, each said HOE (4) being adapted to couple into the structure of the data carrier (1) light of the same selected wavelength which is incident thereto from the same selected direction (6) and to cause the transmission thereof as aforesaid (7) to respective said second locations (10) which lie along a track parallel to the first-mentioned track.
Claim 6
Dependent Claim
81 words
A data carrier (1) according to any one of claims 1 to 3 comprising a plurality of said HOEs (4) disposed in a distributed coded array, said HOEs (4) being adapted to couple into the structure of the data carrier (1) simultaneously light of a respective selected wavelength which is incident thereto simultaneously from respective selected directions and to cause the simultaneous transmission thereof as aforesaid (7) to respective said second locations (10) which are disposed in a second distributed array.
Claim 7
Dependent Claim
83 words
A data carrier (1) according to any preceding claim wherein the or at least one of said HOE(s) (4) is in the form of a multiple HOE (4) adapted to couple into the structure of the data carrier (1) light of a selected wavelength which is incident thereto from a selected direction (6) and to cause the transmission thereof as aforesaid (7) simultaneously in different directions through the structure of the data carrier (1) to a plurality of separate said second locations (10A,10B,10C).
Claim 8
Dependent Claim
78 words
A data carrier (1) according to any preceding claim incorporating, at a predetermined location in the respective transmission path through the data carrier of light coupled thereinto by the or each said HOE (4), a dye which is adapted to alter its optical characteristics to prevent the transmission of such light (7) to the respective said second location when said dye is heated above a predetermined temperature or is exposed to a predetermined intensity or wavelength of light.
Claim 9
Dependent Claim
38 words
A data carrier (1) according to claim 3 or to any other preceding claim when appended thereto, comprising also a transmission display hologram which is adapted to be illuminated by light reflected from said specular reflective surface (3).
Claim 10
Dependent Claim
158 words
A data carrier (101) bearing at least one holographic optical element (HOE) (104), characterised in that the data carrier (101) is constructed such as to trap within its structure light (106) of a selected wavelength which is incident thereto at a selected angle through an element (111) of selected refractive index placed into contact with an exposed surface of the data carrier (101) at one or more first locations, and to transmit the same (106) through its structure to one or more respective second locations spaced from the first location(s) by a process involving total internal reflection of such light (106) at said exposed surface; and in that the data carrier (1) bears at the or each said second location a said HOE (104) which is adapted to couple out of the structure of the data carrier (101) in a selected direction (107) light which is incident thereto by transmission from (the respective) said first location as aforesaid.
Claim 11
Dependent Claim
158 words
A data carrier (101) bearing at least one holographic optical element (HOE) (104), characterised in that the data carrier (101) is constructed such as to trap within its structure light (106) of a selected wavelength which is incident thereto at a selected angle through an element (111) of selected refractive index placed into contact with an exposed surface of the data carrier (101) at one or more first locations, and to transmit the same (106) through its structure to one or more respective second locations spaced from the first location(s) by a process involving total internal reflection of such light (106) at said exposed surface; and in that the data carrier (1) bears at the or each said second location a said HOE (104) which is adapted to couple out of the structure of the data carrier (101) in a selected direction (107) light which is incident thereto by transmission from (the respective) said first location as aforesaid.
Claim 12
Dependent Claim
40 words
A data carrier (101) according to claim 9 constructed such as to transmit the light (106) trapped as aforesaid to said second location(s) by a process involving total internal reflection of such light (106) at two opposite exposed surfaces thereof.
Claim 13
Dependent Claim
65 words
A data carrier (101) according to claim 9 constructed such as to transmit the light (106) trapped as aforesaid to said second location(s) by a process involving total internal reflection of such light (106) at said exposed surface and reflection of such light (106) at a specular reflective surface (108) provided within the structure of the data carrier (101) in parallel with said exposed surface.
Claim 14
Dependent Claim
79 words
A data carrier (101) according to any one of claims 9 to 11 comprising a plurality of said HOEs (104) disposed in a coded track, each said HOE (104) being adapted to couple out of the structure of the data carrier (101) in the same selected direction (107) light of the same selected wavelength which is incident thereto (106) by transmission as aforesaid from respective said first locations (109) which lie along a track parallel to the first-mentioned track.
Claim 15
Dependent Claim
77 words
A data carrier (101) according to any one of claims 9 to 11 comprising a plurality of said HOEs (104) disposed in a distributed coded array, said HOEs (104) being adapted to couple out of the structure of the data carrier (101) simultaneously in respective selected directions light of a respective selected wavelength which is incident thereto (106) simultaneously by transmission as aforesaid from respective said first locations (109) which are disposed in a second distributed array.
Claim 16
Dependent Claim
74 words
A data carrier (101) according to any one of claims 9 to 13 wherein the or at least one of said HOE(s) (104) is in the form of a multiple HOE (104) adapted to couple out of the structure of the data carrier (101) simultaneously in a plurality of different selected directions (107) light of a selected wavelength which is incident thereto (106) by transmission as aforesaid from the respective said first location (109).
Claim 17
Dependent Claim
84 words
A data carrier (101) according to any one of claims 9 to 14 incorporating, at a predetermined location in the respective transmission path through the data carrier (101) of light transmitted as aforesaid (106) to the or each said HOE (104), a dye which is adapted to alter its optical characteristics to prevent the transmission of such light (106) to the respective HOE (104) when said dye is heated above a predetermined temperature or is exposed to a predetermined intensity or wavelength of light.
Claim 18
Dependent Claim
38 words
A data carrier (101) according to claim 11 or to any other preceding claim when appended thereto, comprising also a transmission display hologram which is adapted to be illuminated by light reflected from said specular reflective surface (108).
Claim 19
Dependent Claim
163 words
A reading apparatus for a data carrier (1) according to any one of claims 1 to 8, characterised by: at least one light emitter (9) whereby the or each said HOE (4) of a said data carrier (1) can be illuminated with light of the said selected wavelength from the said selected direction (6) when the data carrier (1) is received within the reading apparatus; at least one element (11) of selected refractive index which is adapted to be placed into contact with said exposed surface of the data carrier (1) at the respective said second location(s) thereof simultaneously with the illumination of the respective HOE (4) as aforesaid, whereby the light transmitted to the respective said second location(s) as aforesaid (7) can be coupled out of the structure of the data carrier (1) through said element(s) (11); and at least one light detector (12) for detecting light coupled out of the structure of a said data carrier (1) through said element(s) (11).
Claim 20
Dependent Claim
143 words
A reading apparatus for a data carrier (101) according to any one of claims 9 to 16, characterised by: at least one light emitter (110) with an associated element (111) of selected refractive index which is adapted to be placed into contact with said exposed surface of a said data carrier (101) at one or more said first locations thereof when the data carrier (101) is received within the reading apparatus, whereby to direct light of said selected wavelength from said emitter (110) through said element (111) at said selected angle to be trapped within the structure of the data carrier (101); and at least one light detector (112) for detecting such trapped light which is transmitted (106) from said first location(s) and coupled out (107) of the structure of the data carrier (101) by one or more said HOE(s) (104) as aforesaid.
Claim 21
Dependent Claim
29 words
A reading apparatus according to claim 17 or claim 18 wherein said element (11,111) of selected refractive index is in the form of a roller of compressible material (11,111).
Claim 22
Independent Claim
121 words
A method of manufacturing a thick-film HOE (4) for a data carrier (1) according to any one of claims 1 to 8 which comprises the step of interfering within the volume of a holographic recording medium (3) two specular, mutually coherent beams of light incident thereto from selected directions, the incidence angle of the said beam which corresponds to the reconstructed beam (7) of the finished HOE (4) being steeper than the desired angle of such reconstructed beam (7); characterised by the subsequent step of swelling said medium (3) whereby to reduce the angle of such reconstructed beam (7) to enable its transmission through the structure of the finished data carrier (1) by a process involving total internal reflection as aforesaid.
Claim 23
Independent Claim
130 words
A method of manufacturing a thick-film HOE (104) for a data carrier (101) according to any one of claims 9 to 16 which comprises the step of interfering within the volume of a holographic recording medium (103) two specular, mutually coherent beams of light incident thereto from selected directions, the incidence angle of the said beam which corresponds to the incident beam (106) for the finished HOE (104) being steeper than the desired angle of such incident beam (106); characterised by the subsequent step of swelling said medium (103) whereby to reduce the angle of such incident beam (106) to enable the HOE (104) to reconstruct from a beam transmitted to it through the structure of the finished data carrier (101) by a process involving total internal reflection as aforesaid.
Claim 24
Dependent Claim
32 words
A method according to claim 20 or claim 21 wherein said swelling step is effective also to change the reconstruction wavelength of the HOE (4,104) from the visible to the infra-red band.
References Cited (Backward Citations)
No citation records indexed.
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