Abstract: The invention relates to an anticounterfeiting device comprising a form birefringent surface relief structure bearing a colored three-dimensional polarization image. The structure may be composed of pixels whose surface relief microstructure and composition determines the direction and color of zero-order diffracted light visible from each pixel when the structure is illuminated with polarized light and viewed through an analyzer that passes light of the opposite polarization.
Abstract: An anticounterfeiting device comprising a surface relief structure having both diffractive and polarizing properties. Polarization of reflected light is controlled by the orientation and composition of a fine grating structure whose shortest period is substantially smaller than the wavelength of visible light; and diffraction is controlled by a longer period component of the grating structure having a second orientation. Presence and arrangement of the polarizing properties of the device are detected by illuminating the device with polarized light and viewing the reflected light, or by illuminating the device with unpolarized light and viewing reflected light through a polarizer. Because such a device is difficult to copy or reverse engineer precisely, the authenticity of the device can be judged by the presence and arrangement of the polarization properties and the diffraction properties in the device.
Abstract: A video image viewing device includes first and second glass plates having a layer of liquid crystal therebetween. A plurality of laser diodes extending along a line near one edge of the first plate are selectively illuminated at an intensity corresponding to the amplitude of a video signal during each of a plurality of video lines. The light propagates through the first plate via total internal reflection not entering the liquid crystal layer until it reaches an area where the refractive index of the liquid crystal is selectively modified. The refractive index may be modified by selectively energizing each of a plurality of horizontal strip electrodes vertically spaced from each other. The electrodes are sequentially energized to frustrate the total internal refraction and thereby cause the light to be transmitted through the liquid crystal layer into the second plate at a location corresponding to the location of video line in a video frame of the video signal.
Type:
Grant
Filed:
July 16, 1999
Date of Patent:
January 30, 2001
Assignee:
New Light Industries, Ltd.
Inventors:
Stephen P. McGrew, P. David DeVries, Roger F. Wink, David H. Foster
Abstract: A video image viewing device includes first and second glass plates having a layer of liquid crystal therebetween. A plurality of laser diodes extending along a line near one edge of the first plate are selectively illuminated at an intensity corresponding to the amplitude of a video signal during each of a plurality of video lines. The light propagates through the first plate via total internal reflection not entering the liquid crystal layer until it reaches an area where the refractive index of the liquid crystal is selectively modified. The refractive index may be modified by selectively energizing each of a plurality of horizontal strip electrodes vertically spaced from each other. The electrodes are sequentially energized to frustrate the total internal refraction and thereby cause the light to be transmitted through the liquid crystal layer into the second plate at a location corresponding to the location of video line in a video frame of the video signal.
Type:
Grant
Filed:
May 13, 1997
Date of Patent:
October 26, 1999
Assignee:
New Light Industries, Ltd.
Inventors:
Stephen P. McGrew, P. David DeVries, Roger F. Wink, David H. Foster