AU2004317631A1 - A method of forming a rainbow security hologram - Google Patents
A method of forming a rainbow security hologram Download PDFInfo
- Publication number
- AU2004317631A1 AU2004317631A1 AU2004317631A AU2004317631A AU2004317631A1 AU 2004317631 A1 AU2004317631 A1 AU 2004317631A1 AU 2004317631 A AU2004317631 A AU 2004317631A AU 2004317631 A AU2004317631 A AU 2004317631A AU 2004317631 A1 AU2004317631 A1 AU 2004317631A1
- Authority
- AU
- Australia
- Prior art keywords
- hologram
- assigned
- different
- verifying
- reference beam
- 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.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims description 70
- 239000003086 colorant Substances 0.000 claims description 27
- 238000012795 verification Methods 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 10
- 238000007689 inspection Methods 0.000 claims description 9
- 238000005286 illumination Methods 0.000 claims description 8
- 238000011179 visual inspection Methods 0.000 claims description 5
- 230000001427 coherent effect Effects 0.000 claims description 4
- 230000002452 interceptive effect Effects 0.000 claims description 2
- 230000000007 visual effect Effects 0.000 description 5
- 230000000873 masking effect Effects 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 238000010348 incorporation Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/08—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means
- G06K19/10—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means at least one kind of marking being used for authentication, e.g. of credit or identity cards
- G06K19/16—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code using markings of different kinds or more than one marking of the same kind in the same record carrier, e.g. one marking being sensed by optical and the other by magnetic means at least one kind of marking being used for authentication, e.g. of credit or identity cards the marking being a hologram or diffraction grating
-
- 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
- G03H1/24—Processes or apparatus for obtaining an optical image from holograms using white light, e.g. rainbow holograms
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
- G03H1/0005—Adaptation of holography to specific applications
- G03H1/0011—Adaptation of holography to specific applications for security or authentication
- G03H2001/0016—Covert holograms or holobjects requiring additional knowledge to be perceived, e.g. holobject reconstructed only under IR illumination
-
- 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
- G03H2001/2263—Multicoloured holobject
- G03H2001/2268—Rainbow hologram
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2222/00—Light sources or light beam properties
- G03H2222/10—Spectral composition
- G03H2222/17—White light
- G03H2222/18—RGB trichrome light
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
- G03H2223/00—Optical components
- G03H2223/12—Amplitude mask, e.g. diaphragm, Louver filter
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Holo Graphy (AREA)
- Credit Cards Or The Like (AREA)
Description
WO 2005/093648 PCT/IN2004/000071 A METHOD OF FORMING A RAINBOW SECURITY HOLOGRAM TECHNICAL FIELD The present invention relates to a method of forming and validating a color-assigned rainbow security hologram of an object, where different parts of the recreated image of the 5 object is presented to a viewer in different pre-chosen or assigned colors such that a novel in-built security verification/identification feature is encrypted/incorporated into these holograms, which can only be read/verified be using an encoded key hologram. The method of the present invention is useful for commercial and industrial applications and is particularly useful for making counterfeit-proof security emboss hologram masters, 10 where a new type of rainbow security hologram is required which is sometimes referred to as color-assigned rainbow security hologram. The typical property and important advantage of these color-assigned rainbow security holograms is that the different parts of the recreated image of the object is presented to a viewer in different pre-chosen or assigned colors such that a novel in-built security verification/identification feature is 15 encrypted/incorporated into these holograms which can only be read/verified by using an encoded key hologram in the reading process thereby making them suitable for both visual and as well as machine inspection and also in preventing the duplication/counterfeiting of these holograms. BACKGROUND OF THE INVENTION 20 In recent years, emboss holograms, enabling multi-colored visual inspection, have been widely used as security seals on various products to guard against duplication as well as on valuable documents to protect against forgery. One of the important steps in the production of emboss holograms involve the development of rainbow hologram masters. The rainbow holograms are normally formed by using a two-step recording process. Here, 25 a master hologram of an object (0) is constructed in the first step with a conventional off axis hologram recording technique. In the second step, this master hologram is used to fonn the rainbow hologram. For forming this, the master hologram is masked with a suitable horizontal slit aperture, and a real image of '0' (with unit magnification) is projected onto the rainbow holorm recording plate. This real image serves as the input 30 object field in making the rainbow'hsologram. On illumination with white-light, these WO 2005/093648 PCT/IN2004/000071 2 holograms provide clear, sharp, colorful and deep images. As the viewer moves his head up or down, the color of the image appears to change throughout the spectrum (thus the name rainbow hologram). Thus, in a regular rainbow hologram, the entire image will appear in one given color for a particular view point and the viewer does not have any 5 choice of seeing any particular portion of the object in a desired color. Further, due to the rapid technological advances especially in the area of computers, CCD-technology, image processing software, color scanners, printers and copiers etc, it is visualized that the counterfeiters may find it increasingly simple to acquire a holographic pattern/image from an embossed security hologram and subsequently may be able to synthesize a 10 counterfeit/duplicate hologram by using commercially available hologram producing equipment. In view of wide ranging commercial and industrial "applications and also for making counterfeit-proof security emboss hologram masters, a new type of color-assigned rainbow security hologram is required. Thus, methods for making color-assigned rainbow security 15 holograms, with a typical property and important advantage of presenting the different parts of the recreated image of the object to a viewer in different pre-chosen or assigned colors such that a novel in-built security verification/ identification feature is encrypted/ incorporated into these holograms which can only be read/verified by using an encoded key hologram in the reading process and thereby making them suitable for both visual and 20 as well as machine inspection and also in preventing the duplication/counterfeiting of these holograms, have been strongly demanded. OBJECT OF THE PRESENT INVENTION The main object of the present invention is to provide a simple, cost effective and reliable method for making color-assigned rainbow security holograms, where different parts of the 25 recreated image of the object is presented to a viewer in a different pre-chosen or pre assigned colors such that a novel in-built security verification/identification feature is encrypted into these holograms, which can only be read/verified be using an encoded key hologram. Another object of the present invention is to provide a method for making color-assigned 30 rainbow security holograms, which are suitable for both visual and as well as machine WO 2005/093648 PCT/IN2004/000071 3 inspection. Yet another object of the present invention is to provide a method for making color assigned rainbow security holograms which are useful for security applications and also in 5 preventing the duplication/counterfeiting of these holograms. BRIEF SUMMARY OF THE INVENTION To attain the above described objects, the present invention provides a simple, cost effective and reliable method for making color-assigned rainbow security holograms, where different paits of the recreated image of the object is presented to a viewer in 10 different pre chosen or assigned colors such that a novel in-built security verification/ identification feature is encrypted into these holograms, which can only be read/verified be using an encoded key hologram. In addition the present invention provides a method for making color-assigned rainbow security holograms which are suitable for both visual and as well as machine inspection and are useful for security applications and also in 15 preventing the duplication/counterfeiting of these holograms. DETAILED DESCRIPTION OF THE INVENTION Accordingly, the present invention provides a method of forming a rainbow security hologram of an object having different colors assigned at different locations on the object, said method comprising the step of forming different parts of the object with different 20 grating values, wherein the grating value at a particular location determines the color assigned to said location. More particularly, the present invention prQvides a method of forcing a rainbow security hologram of an object having different colors assigned at different locations, said method comprising the steps of 25 (a) splitting a coherent light into a reference beam and one object beam; (b) directing the reference beam and the object beam along separate paths such that the reference beam and the object beam interferes on a photo sensitive material on which the hologram is to be formed, and (c) essentially directing the reference beam directly on the photo sensitive material and 30 the object beam to pass through a Slit Master Hologram (SMH) recording plate having the object formed on it wherein different parts of the object are formed by WO 2005/093648 PCT/IN2004/000071 4 different grating values on the SMH, before the same interferes with the reference beam on the photo sensitive material. In an embodiment of the present invention wherein in step. (a), the coherent light is a laser beam. 5 In another embodiment of the present invention wherein in step (a), wherein laser beam is generated by a He-Ne laser or a high intensity laser diode. In yet another embodiment of the present invention wherein in step (a), the laser beam is split into a reference beam & an object beam by a variable beam splitter. In still another embodiment of the present invention wherein in step (b), the reference 10 beam and the object beam are directed along separate paths using plurality of reflecting surfaces. In a further embodiment of the present invention the reference beam and the object beam are directed along separate paths using at least two reflecting surfaces. In a further more embodiment of the present invention the reflecting surfaces are complete 15 or partial reflecting surfaces. In one more embodiment of the present invention, the reflecting surfaces are plane reflecting mirrors. In one another embodiment of the present invention the reference beam and the object beam individually are optionally are allowed to pass through a beam expander and 20 collimating lens before interfering on the photo sensitive material. In another embodiment of the present invention the grating value at a particular location of the object forned on SMH determines the color assigned to said location of the object when formed on photo sensitive material. In yet another embodiment of the present invention wherein in step (c), slit master 25 hologram recording plate (SMH) has different grating value for different wavelength. In still another embodiment of the present invention wherein the grating value for a particular wavelength of light at a predetermined angle of illumination and angle of view is give by the formula d = X/(Sin 01 + Sin 0,) wherein 0, = angle of view , Oi = angle of illumination, d is grating value and X is wavelength of light. 30 The present invention also provides a method of authenticating /verifying a color assigned WO 2005/093648 PCT/IN2004/000071 5 rainbow security hologram imposed with an image of an object, wherein different locations of the object have different pre assigned colors using which an authenticating hologram is prepared, said method comprising the steps of (a) obtaining a reference beam; 5 (b) projecting the reference beam through a Slit Master Hologram (SMH) to obtain a decoding reference beam, (c) projecting the decoding beam on to the hologram which is to be authenticated such that an image of the object is formed, and (d) verifying the image thus formed using a photo detector to authenticate the hologram. 10 In an embodiment of the present invention wherein in step (a), the reference beam is obtaining from source of He-Ne laser or high intensity laser diode. In another embodiment of the present invention wherein in step (b), the reference beam is allowed to pass through a beam expander and a collimating lens before passing. through Slit Master Hologram (SMH). 15 In still another embodiment of the present invention wherein in step (b), slit master hologram recording plate (SMH) has different grating value for different wavelength. In yet another embodiment of the present invention wherein in step (c), verification includes analyzing the of the image formed and authenticating the hologram if the colors of various parts of the images formed are in a pre assigned format. 20 In a further embodiment of the present invention wherein in step (c), verification includes the steps of (a) analyzing the colors of various pa'ts of the image; (b) matching the colors of various parts of the image with a pre assigned format, and (c) verifying the hologram to be authenticate if the colors of various parts of the image 25 are in the pre assigned format. In one more embodiment of the present invention wherein in step (d), the photo detector is placed at the position where reconstructed image of the object is formed. In another embodiment of the present invention wherein in step (d), the photo detector is used in conjunction with a threshold circuit for verifying the image formed. 30 In a further more embodiment of the present invention the method of authenticating WO 2005/093648 PCT/IN2004/000071 6 /verifying is used for machine inspection in addition to visual inspection for color assigned security hologram. For making color-assigned rainbow security holograms having the properties as described above, a decision is first made as to which parts of the object the viewer wants to see in 5 different pre assigned colors at a particular viewing position. Accordingly the desired different colors are assigned to the different parts of the object, which the viewer would ultimately be presented in the final image. Now in the first recording step of the method (FIG. I and FIG. 2), three spatially separated slit master holograms (SMH), for pre assigned different parts of the object, are formed on the same hologram recording plate 10 using an off-axis hologram recording technique. This SMH plate is then used in the second recording step of the method (FIG.3) to construct a color-assigned rainbow security hologram. Here in this case, for encryption/incorporation of a novel in-built security verification/identification feature into these holograms, a convergent reference beam is used to make the color-assigned rainbow security holograms. 15 On illumination with white-light, these color-assigned rainbow security holograms provide different parts of the recreated image of the object to a viewer in different pre chosen or assigned colors at a particular view point. The authenticity of these color-assigned rainbow security holograms is verified/identified by using an encoded key hologram in the final reading process (FIG.4). Here in this case, the slit master holograms (SMH) recorded plate, 20 as formed in the first recording step of the method, serves as the encoded key hologram. In this final reading process, a sharp focus (bright spot) emerges only when the decoding reconstructing beam generated from the encoded key hologram illuminates an authentic color-assigned rainbow security hologram. In this case, with a photo-electric detector, used in conjunction with a threshold circuit, placed at the position of reconstructed sharp focus 25 (bright spot) facilitates automatic verification/identification of the authenticity of the color assigned rainbow security holograms thereby making them suitable for machine inspection in addition to visual inspection. The invention accordingly comprises the features of the above-described objects and relates to the development and investigation of a method for making coldr-assigned 30 rainbow security holograms and the scope of the invention will be indicated in the claims.
WO 2005/093648 PCT/IN2004/000071 7 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a configuration of a recording set up for making slit master holograms according to a first embodiment of the invention. The various parts of the configuration have been labeled as under: 5 1 He-Ne laser 2 Variable beam splitter 3,4 Plane reflecting mirror 5 Spatial filter assembly 6 Beam expander 10 7 Collimating lens 8 3-D Object 9 Collimated reference beam 10 Slit master hologram recording plate FIG.2 is a schematic of a partially cutaway orthogonal view of a recording set up for 15 making slit master holograms shown in FIG.l. The various parts of the configuration have been labeled as under: 1 Object beam 2 Collimated reference beam 3 3-D Object 20 4 Slit master hologram recording plate FIG.3 is a schematic view of a configuration of recording set up for making colour assigned rainbow security hologram according to a second embodiment of the invention. The various parts of the configuration have been labeled as under: 1 He-Ne laser 25 2 Variable beam splitter 3,4,5 Plane reflecting mirror 6 Spatial filter assembly 7,8,10 Collimating lens 9 Beam expander 30 11 Slit master hologram WO 2005/093648 PCT/IN2004/000071 8 12 Object beam 13 Convergent reference beam 14 Colour-assigned rainbow security hologram recording plate FIG.4 is a schematic view of a configuration of reading set up for authenticity 5 verification/identification of colour-assigned rainbow security holograms according to a third embodiment of the invention. The various parts of the configuration have been labeled as under: 1 He-Ne laser 2 Beam Expander 10 3 Collimating lens 4 Collimated reading beam 5 Encoded key hologram [Here slit master holograms (SMH) recorded plate, as formed in the first recording step, serves as an encoded key hologram] 6 Decoding reconstructing beam 15 7 Colour-assigned rainbow security hologram 8 Photo-electric detector 9 Threshold circuit DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the invention will now be described in detail with reference to the 20 accompanying drawings, which are given by way of illustration and the same should not be construed to limit the scope of the invention in any manner. As it can be evident, a person skilled in the art would be ible to create gratings of different values by different pnethods such as by using a computer controlled laser beam thus, the scope of the present invention is not intended to be restricted by the methods described here below and is only 25 restricted by claim 1 which defines the novel and inventive feature of the present invention. FIG.1 is a schematic view of a configuration of a recording set up for making slit master holograms according to a first embodiment of the invention. FIG.2 is a schematic of a partially cutaway orthogonal view of a recording set up for making slit master holograms 30 shown in FIG. 1. It may be noted that a recorded hologram can also be considered to be a WO 2005/093648 PCT/IN2004/000071 9 form of complex grating, satisfying the following equation: Sin Oi+ Sin Ov =/d where Gi is angle of illumination, Ov is angle of view, k is wavelength of light, and d is grating spacing. 5 As shown in FIG. 1 and FIG. 2, the first recording step of the method involves formation of three spatially separated slit master holograms (SMH), for pre assigned different parts of th'e object, on the same hologram recording plate using a conventional off-axis hologram recording technique. For this a decision is first made as to which parts of the object the viewer wants to see in different assigned colours at a particular viewing position. 10 Accordingly the desired different colours are assigned to the different parts of the object, which the viewer would ultimately be presented in the final image. Consider a typical situation, where the viewer wants to see one part of the object in red colour (labeled as 'Or'), second part of the object in green colour (labeled as 'Og') and third part of the object in blue colour (labeled as 'Ob'). Now a slit master hologram (SMHr) for 15 the red assigned colour is first made by using the object part 'Or' only while masking the object parts 'Og' and 'Ob' and other portions of the slit master hologram (SMH) recording plate. Then, slit master hologram (SMHg) for green assigned colour is made, by using the object part ' 0 g' only while masking the object parts 'Or' and 'Ob' and other portions of the SMH recording plate. Similarly slit master hologram (SMHb) for blue assigned colour is 20 made by using the object part 'Ob' only while masking the object parts 'Or' and 'Og' and other portions of the SMH recording plate. This SMH plate is subsequently used in the second recording step of the method to construct a colour-assigned rainbow security hologram. In order to get the entire object parts 'Or', ' 0 g' and 'Ob ' imaged in assigned red, green and blue colours simultaneously at the desired viewing zone, we have used the 25 grating equation (1). By using equation (1), we observe that for a typical value of angle '6i we wish to get the value of angle '9v' constant for all the three red, green and blue (Xr, Xg, Xb) coloured images. For achieving this, we are required to change the value of 'd' [the grating (hologram) spacing] for different AT, Xg, and Xb. Different values of 'd' {'dr' for Xr, 'dg' for Xg and 'db' for Xb} are obtained by altering the angles '6r between ' 0 r' and 30 reference beam; '6g' between 'Og ' and reference beam; 'Ob' between 'Ob ' and reference WO 2005/093648 PCT/IN2004/000071 10 beam while making the three spatially separated, 'SMHr', 'SMHg' and 'SMHb' on the same SMH recording plate in the first recording step of the method. FIG.3 is a schematic view of a configuration of recording set up for making colour assigned rainbow security holograms according to the second embodiment of the 5 invention. As shown in the figure, the SMH plate (as formed in the first recording step of the method) is now used in the second recording step of the method to construct a colour assigned rainbow security hologram. The real image derived from the SMH plate, which serves as the input object field, in conjunction with a convergent reference beam (13) is used in the construction of a colour-assigned rainbow security hologram (14). The use of 10 convergent reference beam, in this recording step of the method, also facilitates in the encryption/incorporation of a novel inbuilt security verification/identification feature into these colour-assigned rainbow security holograms. On illumination with white-light, these colour-assigned rainbow security holograms provide different parts of the recreated image of the object to a viewer in different pre 15 chosen or assigned colours at a particular view point. FIG.4 is a schematic view of a configuration of reading set up for authenticity verification/identification of colour-assigned rainbow security holograms according to a third embodiment of the invention. The authenticity of these colour-assigned rainbow security holograms is verified/identified by using an encoded key hologram in the final 20 reading process. Here in this case, the slit master holograms (SMH) recorded plate, as formed in the first recording step of the method, serves as the encoded key hologram. In this final reading process, a shatp focus (bright spot) emerges only when the decoding reconstructing beam (6) generated from the encoded key hologram (5) illuminates an authentic colour-assigned rainbow security hologram (7). In this case, with a photo-electric 25 detector (8), used in conjunction with a threshold circuit (9), placed at the position of reconstructed sharp focus (bright spot) facilitates automatic verification/identification of the authenticity of these colour-assigned rainbow security holograms thereby making them suitable for machine inspection in addition to visual inspection. We have successfully made the colour-assigned rainbow security holograms by using this 30 invented method in our laboratory.
WO 2005/093648 PCT/IN2004/000071 11 Here a method for making colour-assigned rainbow security holograms according to the present invention has been described above on the basis of the principles and embodiments thereof. It is clear from the foregoing description that the method for making colour-assigned 5 rainbow security holograms according to the invention is advantageous in that it provides a simple, cost effective and reliable method for making colour-assigned rainbow security holograms, where different parts of the recreated image of the object is presented to a viewer in different pre-chosen or assigned colours such that a novel inbuilt security verification/identification feature is encrypted/incorporated into these holograms, which 10 can only be read/verified be using an encoded key hologram. In addition the method for making colour-assigned rainbow security holograms according to the invention is advantageous in that it provides a method for making colour-assigned rainbow security hologram which are suitable for both visual and as well as machine inspection, and are useful for security applications and also in preventing the 15 duplication/counterfeiting of these holograms.
Claims (22)
1. A method of forming a rainbow security hologram of an object having different colors assigned at different locations on the object , said method comprising the step of forming different parts of the object with different grating values, wherein 5 the grating value at a particular location determines the color assigned to said location.
2. A method of forming a rainbow security hologram of an object having different colors assigned at different locations, said method comprising the steps of a. splitting a coherent light into a reference beam and one object beam; 10 b. directing the reference beam and the object beam along separate paths such that the reference beam and the object beam interferes on a photo sensitive material on which the hologram is to be formed; and c. essentially directing the reference beam directly on the photo sensitive material and the object beam to pass through a Slit Master Hologram (SMH) 15 recording plate having the object formed on it wherein different parts of the object are formed by different grating values on the SMH, before the same interferes with the reference beam on the photo sensitive material.
3. A method as claimed in claim 2 wherein in step (a), the coherent light is a laser 20 beam.
4. A method as claimed in claim 2 wherein in step (a), wherein laser beam is generated by a He-Ne laser or a high intensity laser diode.
5. A method as claimed in claim 2 wherein in step (a), the laser beam is split into a 25 reference beam & an object beam by a variable beam splitter.
6. A method as claimed in claim 1, wherein in step (b), the reference beam and the object beam are directed along separate paths using plurality of reflecting surfaces.
7. A method as claimed in claim 6, wherein the reference beam and the object beam are directed along separate paths using at least two reflecting surfaces. 30
8. A method as claimed in claim 6, wherein the reflecting surfaces are complete or partial reflecting surfaces. WO 2005/093648 PCT/IN2004/000071 13
9. A method as claimed in claim 6, wherein the reflecting surfaces are plane reflecting mirrors.
10. A method as claimed in claim 2, wherein the reference beam and the object beam individually are optionally are allowed to pass through a beam expander and 5 collimating lens before interfering on the photo sensitive material.
11. A method as claimed in claim 2, wherein the grating value at a particular location of the object formed on SMH determines the color assigned to said location of the object when formed on photo sensitive material.
12. A method as claimed in claim 1 wherein in step (c), slit master hologram recording 10 plate (SMH) has different grating value for different wavelength.
13. A method as claimed in claim 12, wherein the grating value for a particular wavelength of light at a predetermined angle of illumination and angle of view is give by the formula d =/(Sin 01 + Sin 0y) wherein 0, = angle of view, Gi = angle of illumination, d is grating value and X is wavelength of light. 15
14. A method of authenticating /verifying a color assigned rainbow security hologram imposed with an image of an object, wherein different locations of the object have different pre assigned colors using which an authenticating hologram is prepared, said method comprising the steps of a. obtaining a reference beam; 20 b. projecting the reference beam through a Slit Master Hologram (SMH) to obtain a decoding reference beam, c. projecting the decoding beam on to the hologram which is to be authenticated such that an image of the object is formed, and d. verifying the image thus formed using a photo detector to authenticate the 25 hologram.
15. A method of authenticating / verifying as claimed in claim 14, wherein in step (a), the reference beam is obtaining from source of He-Ne laser or high intensity laser diode.
16. A method of authenticating /verifying as claimed in claim 14 wherein in step (b), the reference beam is allowed to pass through a beam expander and a collimating lens 30 before passing through Slit Master Hologram (SMH). WO 2005/093648 PCT/IN2004/000071 14
17. A method of authenticating /verifying as claimed in claim 14 wherein in step (b), slit master hologram recording plate (SMH) has different grating value for different wavelength.
18. A method of authenticating / verifying as claimed in claim 14 wherein in step (c), 5 verification includes analyzing the of the image formed and authenticating the hologram if the colors of various parts of the images formed are in a pre assigned format.
19. A method of authenticating / verifying as claimed in claim 14 wherein in step (c), verification includes the steps of 10 a) analyzing the colors of various parts of the image matching the colors of various parts of the image with a pre assigned format. b) verifying the hologram to be authenticate if the colors of various parts of the image are in the pre assigned format.
20. A method of authenticating /verifying as claimed in claim 14 wherein in step (d), the 15 photo detector is placed at the position where reconstructed image of the object is formed.
21. A method of authenticating /verifying as claimed in claim 14 wherein in step (d), the photo detector is used in conjunction with a threshold circuit for verifying the image formed. 20
22. A method of authenticating /verifying as claimed in claim 14, is used for machine inspection in addition to visual inspection for color assigned security hologram.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/IN2004/000071 WO2005093648A1 (en) | 2004-03-29 | 2004-03-29 | A method of forming a rainbow security hologram |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2004317631A1 true AU2004317631A1 (en) | 2005-10-06 |
Family
ID=34957308
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2004317631A Abandoned AU2004317631A1 (en) | 2004-03-29 | 2004-03-29 | A method of forming a rainbow security hologram |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU2004317631A1 (en) |
| WO (1) | WO2005093648A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GEP20125395B (en) | 2009-12-16 | 2012-02-10 | Method of code recording for protection of product against falsification and device for its identification |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0375833B1 (en) * | 1988-12-12 | 1993-02-10 | Landis & Gyr Technology Innovation AG | Optically variable planar pattern |
| NL9001616A (en) * | 1990-07-16 | 1992-02-17 | Stichting Daht Foundation | METHOD FOR IDENTIFYING A HOLOGRAM AND DEVICE FOR CARRYING OUT THIS METHOD |
-
2004
- 2004-03-29 WO PCT/IN2004/000071 patent/WO2005093648A1/en active Application Filing
- 2004-03-29 AU AU2004317631A patent/AU2004317631A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| WO2005093648A1 (en) | 2005-10-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4832445A (en) | Security diffraction devices difficult to exactly duplicate | |
| US20080055685A1 (en) | Volume hologram medium | |
| CN108780595B (en) | Identification device, identification method, identification program, and computer-readable medium containing identification program | |
| JP6707926B2 (en) | Identification system, identification method and program | |
| CN106682912A (en) | Method and apparatus for authentication of 3D structure | |
| US20100027082A1 (en) | Security holograms | |
| US20040156081A1 (en) | Passive hidden imaging | |
| AU674521B2 (en) | Holograms having a standard reference colour | |
| CN102597892B (en) | Authenticity determination hologram and fabrication method therefor | |
| US20050219669A1 (en) | Method of forming a rainbow security hologram | |
| AU2004317631A1 (en) | A method of forming a rainbow security hologram | |
| JP2003295744A (en) | Optical information recording medium constituted of computer hologram | |
| Aggarwal et al. | Encoded reference wave security holograms with enhanced features | |
| JP5407603B2 (en) | Hologram and article with hologram attached | |
| JP2006011513A (en) | Verification method of article including blazed grating, device and article | |
| US4989929A (en) | Process of making an achromatic hologram which is adapted to be reconstructed with white light | |
| Kaura et al. | Security holograms readable with an encoded key hologram | |
| JP2002341733A (en) | Display body and method for reproducing information from the same | |
| US20210379921A1 (en) | Optical security device | |
| JP4608769B2 (en) | Hologram check plate | |
| WO2023148432A1 (en) | A camera, a system for detecting an optical identity tag and a method for identification | |
| GB2612174A (en) | Optical authentication structure with augmented reality feature | |
| Aubrecht | Synergy of Moire principles and diffraction by periodic structures in optical devices for document security | |
| JP2009139676A (en) | Method for determining authenticity of lippmann hologram and device for determining authenticity of lippmann hologram |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MK4 | Application lapsed section 142(2)(d) - no continuation fee paid for the application |