Abstract:
This invention relates to the use of holographic optical elements in the design and application of biometric scanning instruments used typically for capturing biometric information such as fingerprints and handprints. Applications of holographic optical elements include providing several novel operational features involving display, annunciation, and control of biometric fingerprint and handprint scanning instruments. The holographic elements may be used to create an active platen. The active platen may be illuminated to project graphical displays on the platen such as time stamps, instructions to users, or feedback on print quality.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims benefit to U.S. Provisional Pat. Appl. No. 60/603,282, filed Aug. 23, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     
    
     BRIEF SUMMARY OF THE INVENTION  
       [0002]     This invention relates to the use of holographic optical elements in the design and application of biometric scanning instruments used typically for capturing biometric information such as fingerprints and handprints to provide enhanced operational features. Holographic optical elements may be used in place of conventional fingerprint scanning elements, such as platens and prisms, to provide the opportunity for fingerprint scanning manufacturers to reduce product development cycle times, reduce product cost, size, and weight, and provide optical design flexibility not afforded by common glass and plastic refractive optical elements.  
         [0003]     The holographic elements may be used to create an active platen. The active platen may be illuminated to project graphical displays on the platen such as time stamps, instructions to users, or feedback on print quality.  
         [0004]     Further embodiments, features, and advantages of the present invention, as well as the structure and operation of the various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES  
       [0005]     The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.  
         [0006]      FIG. 1A  shows a holographic platen that indicates an active platen area for fingerprint capture according to an embodiment of the present invention.  
         [0007]      FIG. 1B  shows a holographic platen that indicates an active platen area for handprint capture according to an embodiment of the present invention.  
         [0008]      FIGS. 2A-2C  show a holographic platen providing three respective print quality feedback indications according to an embodiment of the present invention.  
         [0009]      FIG. 3A  shows a holographic platen having a virtual slider that provides an indication in real-time relating to a print capture according to an embodiment of the present invention.  
         [0010]      FIG. 3B  shows a holographic platen having virtual buttons or keys that can be displayed and monitored for user interactions according to an embodiment of the present invention.  
         [0011]      FIG. 4A  shows a holographic platen with images or text displayed near an active area of the holographic platen according to an embodiment of the present invention.  
         [0012]      FIG. 4B  shows a holographic platen with images or text displayed within an active area of the holographic platen according to an embodiment of the present invention.  
         [0013]      FIG. 5  shows a holographic platen with an animated image area according to an embodiment of the present invention.  
         [0014]      FIG. 6  is an illustration of a system for capturing a fingerprint image according to an embodiment of the present invention. 
     
    
       [0015]     The present invention will be described with reference to the accompanying drawings. The drawing in which an element first appears is typically indicated by the leftmost digit(s) in the corresponding reference number.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0016]     Holography is a method of producing an image by means of optical wave-front reconstruction. In this method, a holographic element is used to reconstruct in detail the wave field emitted by the object to be imaged. To make a holographic image, two optical beams may be used, one of which illuminates the object to be imaged. The other beam, often called a reference beam, is reflected onto an image-capturing screen or plate. Often, the output from a coherent light source (such as a laser) is separated into two beams for the illumination and reference beam purposes. Alternatively, the reference beam may be used to illuminate the object.  
         [0017]     The image-capturing screen, or detector, is exposed simultaneously to the reference beam and the reflected light from the object. The resulting interference pattern recorded by the detector constitutes the reconstructed image, called the hologram. A hologram is a special ‘photograph’ of an object that retains information about the phase of waves coming from the actual object. The hologram is illuminated with a monochromatic optical beam (usually a laser beam). Part of the resulting diffracted wave field is a precise, three-dimensional copy of the original wave reflected by the object.  
         [0018]     Holographic material is used in biometric scanners, such as live print scanners, to capture biometric data and to provide additional operational features. Embodiments of the present invention describes multiple applications of holographic optical elements for providing several novel operational features including, but not limited to, display, annunciation and control of biometric fingerprint and handprint scanning instruments. These operational features with holographic material can also be utilized in other types of instruments where control, display or operator inputs are required.  
         [0019]     While specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the pertinent art will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the present invention. It will be apparent to a person skilled in the pertinent art that this invention can also be employed in a variety of other applications.  
         [0020]      FIG. 6  is an illustration of a system  600  for capturing a holographic image of a print pattern, such as a fingerprint, through holographic material  606 . Holographic material  606  may include any type of holographic material or element including, but not limited to, one or more holographic optical elements (HOEs), holographic diffraction grating(s), holographic filter(s), holographic diffractive optic(s), or combinations thereof. An example HOE may include, but is not limited to, a volume holographic optical element.  
         [0021]     Holographic material  606  may be configured to act as one or more optical components, such as a lens and/or mirror, at various angles of input light. In this way, holographic material  606  can shape and direct incident reference beams to capture desired images including print images as described herein. When holographic material  606  is illuminated by reference beam  602 , a high contrast fingerprint image may be obtained. Reference beam  602  may be produced by, for example, source  616 . Typically, the fingerprint image will be due to frustrated total internal reflection (“TIR”) caused by reference beam  602  at the platen surface  604  of the holographic material  606  in the presence of fingerprint ridges or valleys.  
         [0022]     In a bright-field illumination embodiment, when a finger, for example, is placed in contact with platen surface  604 , the TIR within holographic material  606  is broken by ridges of the finger. Thus, light from reference beam  602  will reflect from areas of platen surface  604  under valleys of the finger, while light absorbed by ridges of the finger will not be reflected. The contrast between the ridges and valleys of the finger form an image  610  that can be viewed by a detector, such as detector  608 . In this embodiment, ridges may appear relatively dark while valleys and background areas may appear relatively bright in the captured print image. Further, holographic material  606  can optionally act to focus image  610  onto a detector  608 . Additional optical elements or optical systems (not shown) can also be added as a further option if additional beam shaping, focusing, magnifying, or directing of image  610  onto detector  608  is desired.  
         [0023]     Alternatively, in a dark-field illumination embodiment light from holographic material  606  on platen  604  may not be directly imaged by detector  608 . In a dark-field illumination embodiment, the finger is directly illuminated, and light entering the print ridges is diffused and reflected back into holographic material  606  in the areas where the print ridges contact platen surface  604  and break TIR. The light reflected from the ridges is focused at image  610 , thereby producing a representative print image. The valleys and background areas may appear relatively dark while ridges may appear relatively bright in the captured print image. Like the bright-field arrangement, holographic material  606  can optionally act to focus image  610  onto detector  608  to capture image  610  in a dark-field arrangement.  
         [0024]     Additional optical elements or optical systems (not shown) can also be added as a further option if additional beam shaping, focusing, magnifying, or directing of image  610  onto detector  608  is desired.  
         [0025]     Reference beam  602  causes holographic platen  606  to transmit image  610  to detector  608 . Other reference beams, such as reference beam  614  from source  618 , may illuminate holographic material  606  to provide holographic material  606  with additional features.  
         [0026]     Certain areas of a holographic platen in a live print scanner can be specially illuminated to actively display a user guide on the holographic platen. For example, the user guide may indicate where a user is to place his or her finger or hand.  FIGS. 1A and 1B  show holographic material  100  having a large holographic platen area  102  capable of receiving one or more fingers or hands of a user. Active areas of holographic platen area  102  may be controlled by reference beams produced by beam source  108 . In  FIG. 1A , an active area  104  is displayed within the platen area  102 , which is controlled by reference beam  110 . Active area  104  provides a visual indication to a user on where to place his or her finger during a live scan. This can help ensure that a user places the proper finger in an optimum location for live print capture. A user can simply see the active area  104  and place his or her finger(s) on area  104 . In one example shown in  FIG. 1A , active area  104  is displayed as a rectangular or square shape located in an approximately center, bottom region of platen area  102 . In certain applications, active area  104  may be especially helpful to guide a user to place his or her finger in the capture of a single fingerprint (flat or roll print), or a four-finger slap print.  
         [0027]     Similarly, as shown in  FIG. 1B , an active area  106  is displayed as a hand shape located in an approximately center region of platen area  102 . Active area  106  may be controlled by, for example, reference beam  112 . In certain applications, active area  106  may be especially helpful to guide a user to place his or her correct hand (right or left) in the capture of a hand or palm print. Active areas  104  and  106  as shown in  FIGS. 1A-1B  are illustrative and not intended to limit the present invention. Active areas  104  and  106  can be illuminated to have different shapes and can be located in different locations within platen area  102  depending upon a particular application and type of print desired to be captured.  
         [0028]     Beam source  108  may be controlled by a controller (not shown). In one embodiment, beam source  108  may produce a single illumination beam to illuminate holographic material  100 . In another embodiment, beam source  108  may be an array of discrete illumination elements which turn on or off in response to the controller, and which can be used to dynamically change text or graphics on holographic material  100 . In yet another embodiment, beam source  108  may be configured to produce an illumination beam which causes holographic material  100  to display predetermined text or graphics, the activation of which is controlled by the controller. In still another embodiment, beam source  108  may pass through an aperture, such as a filter, LCD, or the like, which contains a pattern to be displayed on holographic material  100 .  
         [0029]     According to a further embodiment, certain areas of a holographic platen in a live print scanner can be specially illuminated to provide a quality feedback indication to a user in a live scan. For instance, such a quality feedback indication can indicate whether a captured print is of acceptable or not acceptable quality. In an example shown in  FIGS. 2A-2C  a platen surface  202  of holographic material  200  may provide three respective print quality feedback indications. In  FIG. 2A , platen surface  202  of holographic material  200  is not illuminated, which indicates that no finger or hand has been placed on platen surface  202 . In  FIG. 2B , platen surface  202  is illuminated in a first color (such as red) to produce a first color platen  204 . First color platen  204  indicates that a print captured in a live scan is of an unacceptable quality. In  FIG. 2C , platen surface  202  is illuminated in a second color (such as green) to produce a second color platen  206 . Second color platen  206  indicates that a print captured in a live scan is of an acceptable quality. Any print quality test can be used including, but not limited to, a ridge count test and/or image quality test. First and second color platens  204  and  206  are illustrative and not intended to limit the present invention as other colors, shapes, patterns, and/or indicia can be illuminated to provide an indication of quality.  
         [0030]     According to further embodiments, certain areas of a holographic platen in a live print scanner can be specially illuminated to provide control or other information to a user in a live scan. In one example,  FIG. 3A  shows holographic material  300  having a platen surface  302  and an area  310 . During a live print scan, area  310  is illuminated to display a virtual slider. For example, during a roll print a user rolls his or her finger from one side of a finger to the other on platen  302 . The virtual slider is illuminated to provide real time control information to a user by changing its length to indicate a parameter, such as, rolled finger position or finger roll speed. The length of the slider can change to track where a finger is during its roll based on a detection of the finger&#39;s position. Alternatively, the length of the slider can change in a predetermined fashion to serve as a guide that a user can follow so that a user rolls his or her finger at an acceptable speed.  
         [0031]     In another example,  FIG. 3B  shows holographic material  300  having a platen surface  302  and an area  320 . During a live print scan, area  320  is illuminated to display one or more virtual keys or buttons. The keys or buttons can have text, graphics, icons, colors or other information displayed therein. These keys or buttons can then be monitored for user interaction.  
         [0032]      FIG. 4A  shows holographic material  400  having a platen surface  402  that includes an area  410  with images or text displayed near an active platen area  404  according to an embodiment of the present invention. In one example, the text and/or images can provide instructions to a user to facilitate a live scan capture. For instance, the text can indicate which finger or hand a user is to place and what type of print (e.g., roll or flat print or slap) is to be captured. This example is illustrative and not intended to limit the present invention as other types of instructions or messages can be illuminated in area  410  on holographic platen surface  402 .  
         [0033]      FIG. 4B  shows holographic material  400  having a platen surface  402  that includes images or text illuminated within active platen area  404  according to a further embodiment of the present invention. In one example, date and time information  420  can be displayed. Such date and time information can be helpful in access control, time and attendance, and other applications using live print scanners.  
         [0034]      FIG. 5  shows holographic material  500  with a platen surface  502  that includes an area  504  illuminated with animation according to an embodiment of the present invention. Such animation can include, but is not limited to, one or more predetermined animated holographic images.  
       CONCLUSION  
       [0035]     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.