Title: Security device using a hologram reconstructing a deep image
Application Number: 200510009479 Application Date: 2005.02.16
Publication Number: 1661501 Publication Date: 2005.08.31
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: G03H1/04,G03H1/00
Applicant(s) Name: Du Pont Address:
Inventor(s) Name:
Attorney & Agent: fan zheng
Abstract:
     A holographic optical element (HOE) that is comprised of a deep image hologram and a method for using this HOE as a security device are described. The deep image hologram is viewable with a collimated or at least partially collimated light source having a center wavelength in the visible region of the electromagnetic spectrum and a spectral bandwidth, wherein the spectral bandwidth of the collimated or at least partially collimated light source at least partially overlaps the spectral bandwidth of the deep image hologram. The deep image hologram is not viewable (i.e., appears essentially unrecognizable to the human eye) with a diffuse lighting source, such as ordinary room lighting.
Time: 5