CN1141680C - Guantum dot safety device and method - Google Patents
Guantum dot safety device and method Download PDFInfo
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- CN1141680C CN1141680C CNB001008617A CN00100861A CN1141680C CN 1141680 C CN1141680 C CN 1141680C CN B001008617 A CNB001008617 A CN B001008617A CN 00100861 A CN00100861 A CN 00100861A CN 1141680 C CN1141680 C CN 1141680C
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- quantum dot
- fluorescence
- label
- counterfeit
- reader
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Abstract
The present invention relates to a quantum dot which is used as a fluorescent marker in safety ink, paper, plastics, explosives or other articles or substances which need providing a specific signature or a mark. Quantum dots with a specific size, a specific ingredient and a specific structure can be used for generating specific fluorescence; a quantum dot mixture can be used for generating a random pattern of fluorescence with a changeable spectrum; a specific quantum dot structure can be used for providing desired physical and optical characteristics. The quantum dot can be read by an optical reader which can be combined with a reader which uses another technology.
Description
Technical field
The present invention relates to quantum dot, relate in particular to quantum dot and be used for safety applications.
Background technology
Quantum dot comprises its optics and physical characteristics and manufacture method, existing description and open in following publication:
1.Warren C.W.Chan, " the quanta point biological complex is used for the hypersensitive anisotropy and detects " of Shuming Nie, " science " 281 (5385): 2016
2.Marcel Burchez Jr., Mario Moronne, Peter Gin, Shimon Weiss, " the semiconductor microcrystallite is as the biological label " of A.PaulAlivisators, " science " 281 (5385): 2013
3.L.E.Brus, " applied physics " A53,465 (1991)
4.W.L.Wilson, P.F.Szajowski, L.E.Brus, " science " 262,1242
(1993)5.A.Henglein，Chem.Rev.89，1861(1989)
6.H.Weller，Angew.Chem.Int.Ed.Engl.32，41(1993)
7.M.A.Hines?and?P.Guyot-Sionnest，J.Phys.Chem.100，468(1996)
8.B.O.Dabbousi，et?al.，J.Phys.Chem.B101，9463(1997)
9.C.B.Murray，D.J.Norris，M.G.Bawendi，J.Am.Chem.Soc.115，8706(1993)
10.X.G.Peng，J.Wickham，A.P.Alivasatos，J.Am.Chem.Soc.120，5343(1998)
11.L.M.Lizmarzan，M.Giersig，P.Mulvaney，Langmuir?12，4329(1996)
12.M.A.CorreaDuarte，M.Giersig，L.M.LizMarzan，Chem.Phys.Lett.286，497(1998)
13.Marcel Bruchez Jr., Mario Moronne, Peter Gin, Shimon Weiss, and A.Paul alivisatos, " the semiconductor microcrystallite is as the biological label " " science " 1998September 25; 281:2013-2016.
14.Warren C.W.Chan and Shuming Nie, " the quanta point biological complex is used for the hypersensitive anisotropy and detects " " science " 1998 September 25; 281:2016-2018.
Above-mentioned publication has been described the manufacturing quantum dot, the method for the CdSe crystal that covers as the CdSe-CdS of millimicro meter level and ZnS.This publication has also been described the physics and the optical characteristics of these quantum dots.Especially, in people's such as people's such as Chan article (publication 1) and Burchez Jr. article (publication 2), the quantum dot with following fluorescent characteristic has been described:
High fluorescent can be compared with the rhodamine 6G of 20 molecules;
Emission spectrum is equivalent to 1/3rd of a typical organic dyed labels latex balloon;
Compare with typical organic dyestuff, its photofading rate will be hanged down 100 times;
Long fluorescence lifetime is similar to hundreds of nanoseconds;
Fluorescence spectrum peak value and lateral size of dots have very close mutual relationship.
Summary of the invention
According to an aspect of the present invention, quantum dot can be used as the fluorescence labelling thing in needs provide safety ink, paper, plastics, explosive or other any article or the material of unique signature or mark.Because quantum dot has controllable photoluminescence peak color, unique narrow fluorescence spectrum, long significantly fluorescence lifetime, and can make its fluorescent characteristic be independent of the characteristics such as environment that it contacted basically, therefore, quantum dot is better than the fluorophore of standard in above application.The quantum dot of size, composition and the structure of wishing can be used for producing the fluorescence of hope, and the potpourri of quantum dot can be used for producing the arbitrary graphic pattern with the variable fluorescence of spectrum, and special quantum-dot structure can be used for providing the physics and the optical characteristics of hope.
Description of drawings
Fig. 1 is included in the synoptic diagram that comes marked product among a kind of plastics with quantum dot.
Fig. 2 is the quantum dot synoptic diagram of a gland, represent that a quantum dot has a gland layer and another molecule organic layer, the effect of this organic layer is under the condition of the light that has special wavelength, this quantum dot and additional organic molecule are combined, or combine with suitable organic molecule.
Fig. 3 is the planimetric map of safety label, this safety label has a pad of peeling off, a pressure sensitive adhesive coating, a paper substrate layer of printing by the fluorescence quantum ink, and a transparent hologram that has " window ", see through and should " window " character string be printed on this paper substrate layer.
Fig. 4 is the optical module synoptic diagram of holographic reader, and being used to read with hologram and/or phosphor pattern is the safety label of form, and wherein this phosphor pattern has unique emission spectrum or fluorescence lifetime, for example those characteristics of quantum dot.
Fig. 5 is the skeleton view that is used to read the combined reader of hologram on the printing cards and fluorescence quantum.
The chart of Fig. 6 has shown the difference between the fluorescence of quantum dot fluorescence and typical organic dyestuff.
Fig. 7 is by safety label reader, character string printer, character string and safety label reader and communication network, is used to prevent and/or detect the process flow diagram of the system of counterfeit product.
Embodiment
According to one embodiment of present invention, the fluorescent characteristic of quantum dot can be used for providing a kind of on certain surface or in material the method for canned data, come thereby effective product or document distinguished with invalid product or document.For example, as shown in Figure 1, quantum dot 200 is comprised in by suitable material, as plastics make the eye 210 in.According to following each embodiment of the present invention that will describe, this eye 210 can as Teddy bear, come authorizing product with the difference of unauthorized product.
According to the application of the quantum dot of each embodiment of the present invention, will in following example, give to describe.As shown in Figure 2, a kind of quantum dot-labeled UV-solidifiable ink that is used for anti-counterfeit/safety applications can use by ZnSe and make around outer CdSe quantum dot 500 as gland 520.This is prepared by existing method by the CdSe quantum dot of ZnSe gland, is had the Size Distribution and the optical characteristics of uniqueness by the light 510 of quantum dot emission.For example, because quantum dot has the relevant rate of deposition of size,, quantum dot is pressed its size separation so can use centrifuge method.Alternatively, can use different conditions to make each batch quantum dot in developmental process, depart from its size, then, each batch quantum dot can be mixed selectively, have the potpourri that special size distributes so that prepare out.
As shown in Figure 3, a collection of ready quantum dot potpourri 410 by stirring reasonable time, as four hours, can be suspended in a kind of transparent UV-solidifiable resin, thereby make a kind of fluorescence UV-solidifiable ink 415.Many UV-solidifiable resins and ink can be buied from manufacturer at US and European.In the ink amount of quantum dot can height can be low.This ink is printed in the pattern on the paper stock that has adhesive coating and peeling paper pad 420, is cured by ultraviolet photoetching then.Then this paper that produces is carried out die-cut, to make the autoadhesion label 435 of rolling.
This label 435 can be read by a reader, as shown in Figure 4.This reader comprises an optical system, and it is by the light of suitable wavelength, and for example the light of 514nm throws light on to selected zone on the label.This light is used to read a zone on the label of being printed by quantum dot-labeled ink 415 690.This reader is collected institute's emitted fluorescence 660 from illuminated label, and analyzes its spectrum and time response.A lens combination 635 is focused into a point with this fluorescence light source, and a diffraction grating 615 is extended to its spectrum with this fluorescence light source on the linear array 625 of a photoelectric detector.Electronic circuit passes through the modulation illumination light, and will modulation and institute's emitting fluorescence of this illumination light be compared because of the variation that modulation takes place, thereby the time behavior of this fluorescence is analyzed.
Reader shown in Figure 4 can make up with the reader of other technology of use, for example magnetic strip reader as shown in Figure 5.
By using a kind of short pulse of exciting light to certain sample, and observation post's emitted fluorescence intensity in during hundreds of nanoseconds, the fluorescence of elapsed time parsing can be measured.In this article, " weak point " is to compare with this fluorescence lifetime.Most of fluorescent materials are only launched several nanoseconds light after activating, but the CdSe500 quantum dot of ZnS gland 520 can be launched hundreds of nanoseconds light usually after activating, shown in the right side of Fig. 6.The left side of Fig. 6 demonstrates the difference between quantum dot fluorescence and the typical organic dyestuff fluorescence.Another method of measuring the fluorescence of elapsed time parsing is at this exciting light of one or more frequencies (as kHz-mHz) modulation, and observes the phase relation between this exciting light modulation and the institute's emitted fluorescence light source modulation.More than two kinds of methods can clearly quantum dot fluorescence and organic dyestuff fluorescence be made a distinction.
By observing the three-dimensional spread spectrum of fluorescence, can make a distinction according to the bandwidth of quantum dot fluorescence fluorophore with this quantum dot and other kind.The fluorophore difference that can significantly any counterfeiter of quantum dot and other may be used for reaching identical fluorescent characteristic to the spectrum of fluorescence and the combinatory analysis of time is come.The combination of spectrum and time fluorescent characteristic can be referred to as the fluorescence signature.
Reader shown in Figure 4 when label moves through this reader, reads on this label the fluorescence of each spot signature in a series of flecks.If this quantum dot presents very high concentration, thereby make each spot all comprise the typical sample of a quantum dot potpourri, each spot will produce identical fluorescence signature, and it can only duplicate by the method for duplicating the quantum dot potpourri.Therefore, this fluorescence signature provides the evidence in label source.
Thereby far on average have only one or several quantum dot to exist in each spot if these quantum dots are separated from one another, then each spot will have the fluorescence signature of oneself.This series fluorescence signature can be from a series of spot measurements of whole label, and then determine by the random site of various quantum dots on the label, and all are unique for each label.These a series of fluorescence signatures can be referred to as " phosphor pattern ".
Because the phosphor pattern on each label is unique, thus can be at the phosphor pattern of making on link or the applied links reading tag, and be input in the middle of the database.In sales section or distribution link, these phosphor patterns can be read, and are complementary with pattern in the database then.If certain pattern is detected not in the middle of database, then it is exactly certain counterfeiter evidence of the manufacture method of counterfeit quantum dot-labeled label.
Do not use database because it may require huge communication network, label can add the character string that comprises a kind of printing.This character string contains the enciphered message of representing this phosphor pattern.For example use phosphor pattern can generate this character string as key in a public-key cryptography scheme, this enciphered message can identification (RFID) tag printing person and this information is encrypted and this character string is printed on date on the label.Therefore at the sales section of the product of doing tag processes, reader both can read this phosphor pattern and also can read this character string, deciphered this character string, and extracted enciphered message, thus the validity of verification label and product.
The system that utilizes a kind of safety label reader to be used to prevent and/or detect counterfeit product as shown in Figure 7.This system comprises and uses a character string printer (not shown), character string and safety label reader (not shown), and a communication network (not shown).
The potpourri of quantum dot can be as the marker in the explosive.According to this embodiment of the invention, having a predetermined cun quantum dot that distributes to the greatest extent can join in explosive or other material in the fabrication phase, thereby according to time and/or these materials of place marks of making.
According to another embodiment of the invention, quantum dot can be arranged on a surface upward so that information stores to be provided.Especially can prepare quantum dot in batch, each batch all has unique spot size among a small circle.Each mark words and phrases for special attention all scribble can be photosensitive bonding agent, dichromic acid gel for example.A kind of optical system is focused into very speckle with laser beam scribbling on the surface of first quantum dot, it is similar to micron on diameter, the whole surface of this laser beam flying, open and close according to the position, thereby in this laser beam is when being in open mode, marking words and phrases for special attention first is glued together, and rinsing is carried out to remove not bonding quantum dot in this surface.Coat second for then this surface and mark words and phrases for special attention, repeat this process by different irradiation patterns.Respectively marking words and phrases for special attention subsequently provides the further bonding of different quantum dot sizes with irradiation pattern, and each batch all has own unique pattern.
Because the size of a general quantum dot is less than 4 millimicrons, a surface can hold 6,250,000 quantum dot/square micron or 6,250,000,000,000 point/square centimeter.Can or more prepare quantum dot on the specific dimensions 20 by accurate control growth time and condition or by physical separation method, be similar to 50 with current, 000,000/square centimeter high density magnetic storage density is compared to produce and is similar to 100,000,000,000,000/square centimeter total storage capacity.
The near-field scan optic probe that utilizes a probe size to compare with a quantum dot size can read the information that is stored on the label.
In order to produce the duplicate of quantum dot pattern by batch, can prepare a master pattern by using the method that generates original quantum dot pattern with quantum dot to the unique dna sequence dna mark of the size of this quantum dot.After being ready to complete, master pattern prepares a duplicate then by following steps:
1. master pattern is full of with the quantum dot that scribbles mercaptan demarcation DNA, this mercaptan is delimited DNA and is complementary to the DNA on the respective point on this master pattern, and allows complementary DNA chain synthetic.
2. rinse unnecessary quantum dot from master pattern.
3. prepare a flat glass sheet, at its surperficial vapour deposition one gold plating, this glass sheet is immersed in the ethanolic solution of 11-sulfhydryl undecanoic acid (MUA) of a millimole amount and soaked 18 hours, so that individual layer MUA and gold plating are combined, then, exist under the condition of NaHCO3, how basic L-lysine is being adsorbed onto this individual layer MUA, then, add thiosuccimide-4-(N-maleimide methyl) cyclohexane-1-carboxylate (SSMCC) to this individual layer MUA.This SSMCC and remaining lysine react the surface that comprises the maleimide group that can react with generation.
4. the gold surface of treated this glass sheet is pressed to this master pattern, thereby make a part of mercaptan on each quantum dot delimit DNA and this can react the maleimide set of contact.Allow this master pattern and glass sheet be pressed together and kept 12 hours, this mercaptan demarcation DNA and this maleimide group are reacted, and combine.
5. to the assembling device heating, complementary DNA chain is separated, and this glass sheet and this master pattern are broken away from.Then this glass sheet will have the quantum dot pattern, and it is the mirror image of this master pattern.
This duplicate comprises identical (or corresponding) quantum dot in the pattern identical with master pattern.By same steps as, a plurality of duplicate can be from a master pattern, made, and reproduction making duplicate can be passed through, thus can be from a large amount of duplicate of single master pattern production.
RNA has the similar particular combination characteristic with DNA, makes up as antibody/antigen; These or other any particular combination method all can essentially identical mode be used.
Fluorescent ink as described herein can be applied to the printing process of any standard, as long as it is fit to make quantum dot to be suspended in wherein carrier.A kind of preferred printing process is exactly an inkjet printing, because it can print variable information with the form of dissimilar quantum dots in different printing points.
Method as described herein can make amendment and adjust in every way.For example:
The composition of quantum dot and structure, as the selection of material, and the having or not of different material layers, all can change to produce different absorbabilities and fluorescence property;
This photosensitive adhesive can be selected from any known a lot of photosensitive adhesives;
The density of quantum dot can change in any scope that detects density on the label or in the material; Exciting light can change between long wavelength that can activate employed specific quantum dot and minimal wave length;
The pattern of quantum dot can be that be scheduled to, periodic, quasi periodic or at random on the label;
Any device that can detect the time resolution fluorescence of fluorescence spectrum and/or quantum dot all can use;
Any fluorescent ink, particle, fiber or other structure or material all can use among the opaque reflection hologram or among the transmission hologram or under;
Quantum dot can have the detectable feature of optics, electromagnetism, chemistry, acoustics or mechanical means with any other and combine, so that the anti-counterfeit security mechanism that can further strengthen to be provided;
Any material or structure with adhesion characteristic all can be used in the reproduction process of quantum dot pattern;
Can use that a near field optic scanning probe microscopy, conventional microscope, fluorescent microscope, epifluorescence microscope, spectrofluorimeter or other are any can to read quantum dot pattern or distribution with being in separately or the distribution of the quantum dot under the collocation state or the device that arrangement, position or characteristic make a distinction;
Time resolution fluorescence can use the activation of simple pulse, square-wave pulse, Sine Modulated light or Adaptive Modulation light to detect;
Activation can be realized by any epipolic light and light source of can activating in the quantum dot of LASER Light Source, incandescent lamp, metal vapor discharge light or other;
The photoconductivity of semiconductor-quantum-point or absorption spectrum can be used to detect the existence and the characteristic of quantum dot;
In the present invention, label does not need hologram; They can utilize the combination of quantum dot ink, quantum dot ink and other ink to print simply, can be printed on the paper or other contains quantum dot or carry out on the substrate of coating or covering with the layer that contains quantum dot.
Even should be appreciated that to have provided various embodiment of the present invention and advantage in above description, but above-mentioned disclosing only is illustrative, still can make change in detail, as long as still be retained within the broad principles of the present invention.Therefore, the present invention is only limited by claims.
Claims (25)
1, a kind of anti-counterfeit device includes the quantum dot that is applied in the predetermined pattern, and at the predetermined portions of this pattern, quantum dot has the optics or the physical characteristics of hope.
2, a kind of anti-counterfeit device includes and is applied in a lip-deep quantum dot, but this quantum dot has the characteristic in the sensing range, thus these characteristics can be on this surface random variation from point to points.
3, according to the anti-counterfeit device of claim 2, wherein this quantum dot is by a bunch layout.
4, according to the anti-counterfeit device of claim 2, wherein this surface comprises a paper surface, and it is as external coating with hyaline layer that there is a surface on this paper surface.
5, according to the anti-counterfeit device of claim 4, wherein this hyaline layer comprises that a hot pressing prints to the transmission hologram on the paper.
6, according to the anti-counterfeit device of claim 2, wherein this quantum dot is by it being mixed into a kind of liquid-carrier, this liquid-carrier being coated on this surface again, and by dry or solidify and make this carrier hardening, is applied.
7, a kind of data carrier includes at random size, is arranged in the quantum dot on the surf zone, and this quantum dot is changed selectively, thereby information is encoded according to the distribution of quantum dot in each zone or the selection of characteristic.
8, according to the data carrier of claim 7, the behavior that wherein changes quantum dot selectively comprises the light that has may command and variable wavelength by use, and the selected zone of throwing light on is so that change quantum dot selectively.
9, a kind of data carrier comprises characteristic likely, goes up the quantum dot that selection area combines with the surface, thereby information is encoded according to the distribution of quantum dot in each zone or the selection of characteristic.
10, according to the data carrier of claim 9, wherein this quantum dot is by optics control chemical method or physics control adhesive bonding method, combines with lip-deep selection area.
11, a kind of anti-counterfeit/security system, comprising:
A document, but its have with the quantum dot of the arrangement in the sensing range and
A reader is applicable to the existence and the layout that detect at least a portion quantum dot on the document.
12, a kind of anti-counterfeit/security system, comprising:
But quantum dot is applied to the device of a document with the arrangement in the sensing range;
Detect the existence of at least a portion quantum dot on the document and the device of layout;
The device that this layout is compared with benchmark.
13, a kind of method of mark substance is included in this material and adds quantum dot, but the characteristic that this quantum dot has in the predetermined sensing range distribute, thereby not existing of can detecting that characteristic distributes in certain sample or change.
14, a kind of product of the method manufacturing according to claim 13.
15, a kind of fluorescent ink, comprise Size Distribution with hope and be suspended in can be dry or coagulable liquid-carrier in quantum dot.
16, according to the fluorescent ink of claim 15, wherein this carrier comprises a kind of UV-solidifiable resin.
17, a kind of fluorescent ink with claim 16 is printed on surperficial going up and the product of making.
18, a kind of have a product that strengthens anti-counterfeit ability, and the making of this product utilizes quantum dot and at least one another kind of printing, embossment, mark, sign or resists counterfeit feature or method that composition is combined is finished.
19, a kind of label, its include be included in a kind of can be dry or coagulable adhesive matrix liquid in quantum dot.
20, a kind of fluoresent coating includes the hardened liquid that one deck contains the quantum dot of suspension, and it is arranged from the teeth outwards, and hardening.
21, a kind of safe fine rule that is used for the safety label object comprises a fine rule with a collection of quantum dot coating.
22, a kind of safety label reader comprises:
Be used for device to one group of area illumination on the label;
Be used to detect by the device of quantum dot institute emitted fluorescence on the label and
Be used for determining whether institute's emitted fluorescence has the device for the peculiar feature of quantum dot fluorescence.
23, a kind of safety label reader comprises:
Be used for device to the illumination of the zonule on the label;
Be used to detect device by quantum dot institute emitted fluorescence on the label;
Be used to measure the device of this fluorescent characteristics;
Be used for this reader is moved with respect to label, thus make reader be similar to predetermined pattern and the order, the device of a plurality of positions on the reading tag and
Be used for the device that order and mark sheet with this fluorescence are shown as character string.
24, according to the safety label reader of claim 23, the device that wherein is used to measure this fluorescent characteristics comprises the device of the fluorescence lifetime that is used to measure this fluorescence.
25, according to the safety label reader of claim 23, the device that wherein is used to measure this fluorescent characteristics comprises the device of the fluorescence spectrum that is used to measure this fluorescence.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB031600816A CN100401337C (en) | 2000-02-15 | 2000-02-15 | Quantum point safety device and method |
| CNB001008617A CN1141680C (en) | 2000-02-15 | 2000-02-15 | Guantum dot safety device and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB001008617A CN1141680C (en) | 2000-02-15 | 2000-02-15 | Guantum dot safety device and method |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031600816A Division CN100401337C (en) | 2000-02-15 | 2000-02-15 | Quantum point safety device and method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1309383A CN1309383A (en) | 2001-08-22 |
| CN1141680C true CN1141680C (en) | 2004-03-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB001008617A Expired - Lifetime CN1141680C (en) | 2000-02-15 | 2000-02-15 | Guantum dot safety device and method |
| CNB031600816A Expired - Lifetime CN100401337C (en) | 2000-02-15 | 2000-02-15 | Quantum point safety device and method |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB031600816A Expired - Lifetime CN100401337C (en) | 2000-02-15 | 2000-02-15 | Quantum point safety device and method |
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| Country | Link |
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| CN (2) | CN1141680C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102912675A (en) * | 2012-10-15 | 2013-02-06 | 保定钞票纸业有限公司 | Quantum dot fluorescent anti-counterfeiting paper and manufacturing method thereof |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2015036045A1 (en) * | 2013-09-13 | 2015-03-19 | CSEM Centre Suisse d'Electronique et de Microtechnique SA - Recherche et Développement | Lightguide tamper seal |
| CN106009931B (en) * | 2016-05-05 | 2018-12-07 | 中国科学院长春光学精密机械与物理研究所 | Information ciphering method and encryption system and encryption information read method and reading system |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE69324740D1 (en) * | 1992-08-17 | 1999-06-10 | Thomson Multimedia Sa | Non-counterfeit identification device, reader and identification method |
| CN1027204C (en) * | 1992-09-19 | 1994-12-28 | 南京大学 | Method for preparing visible photoluminescent silicon quantum point |
| CN1090074A (en) * | 1993-01-20 | 1994-07-27 | 陈刚 | The method of making composite holographic label on commodity package |
| EP0721008B1 (en) * | 1995-01-03 | 2000-06-14 | General Electric Company | Quantum splitting oxide phosphors and method of making same |
| CN2266770Y (en) * | 1995-12-21 | 1997-11-05 | 沈良骏 | Random cipher code antifake mark label |
| US5788883A (en) * | 1996-03-29 | 1998-08-04 | General Electric Company | Determination process for determining if quantum splitting phosphors are obtained and novel compositions |
| AP1098A (en) * | 1996-11-20 | 2002-08-29 | Tecsec Incorporated | Cryptographic medium. |
-
2000
- 2000-02-15 CN CNB001008617A patent/CN1141680C/en not_active Expired - Lifetime
- 2000-02-15 CN CNB031600816A patent/CN100401337C/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102912675A (en) * | 2012-10-15 | 2013-02-06 | 保定钞票纸业有限公司 | Quantum dot fluorescent anti-counterfeiting paper and manufacturing method thereof |
| CN102912675B (en) * | 2012-10-15 | 2015-08-12 | 保定钞票纸业有限公司 | A kind of quantum dot fluorescence cheque paper and manufacture method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1309383A (en) | 2001-08-22 |
| CN100401337C (en) | 2008-07-09 |
| CN1495681A (en) | 2004-05-12 |
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