Abstract: Methods for evaluating an optically variable device (“OVD”) or optically variable media (“OVM”) are disclosed. The methods include the steps of applying light of a single wavelength from a calibrated light source to the OVD or OVM; measuring the light diffracted by the OVD or OVM with an integrating sphere; measuring the total incident light on the OVD or OVM; and calculating a diffraction efficiency for the OVD or OVM at the single wavelength based on the measurement of light diffracted and the measurement of total incident light.

Abstract: Apparatus and method for characterizing perceived visual quality of holographic materials, such as diffraction gratings. A white light source directs a collimated beam onto an embossed material. The first order diffracted light strikes a white background directly in view of a digital camera, which records an image. The image is analyzed to calculate total color intensity of the diffracted light and an estimate of the color distinctness. The data is compared to other samples to determine relative visual quality.

Abstract: Apparatus and method for producing optically variable devices, optically variable media, dot matrix holograms or embossing substrates. The system includes: a laser beam generator, a laser beam shaper, a spatial light modulator, imaging optics and an image positioner. The laser beam generator generates a laser beam, which is shaped by the laser beam shaper to modify the laser beam to an optimized beam profile. The shaped laser beam is modulated by the spatial light modulator, which generates, at a place removed from the substrate surface, an optical pattern. The imaging optics causes the optical pattern to be imaged on the substrate surface. An image positioner allows for the optical pattern to be positioned to different areas of the substrate surface.

Abstract: Methods for evaluating an optically variable device (“OVD”) or optically variable media (“OVM”) are disclosed. The methods include the steps of applying light of a single wavelength from a calibrated light source to the OVD or OVM; measuring the light diffracted by the OVD or OVM with an integrating sphere; measuring the total incident light on the OVD or OVM; and calculating a diffraction efficiency for the OVD or OVM at the single wavelength based on the measurement of light diffracted and the measurement of total incident light.

Abstract: A device for reading data from a multi-layered optical disk includes a short coherence-length light source, a beam splitter, an adjustable mirror and an optical detector. The beam splitter is used to form first and second light beams from the short coherence-length light beam. The first light beam is then directed to the optical disk and is reflected by a data mark stored on the optical disk. The second light beam is directed along a reference beam path. The mirror is disposed along the reference beam path and reflects the second light beam back to the beam splitter. The beam splitter recombines the reflected first light beam and the second light beam after the second light beam traverses the reference beam path. The optical detector detects the data mark by constructive interference of the combined reflected first light beam and the second light beam.

Abstract: The present invention relates to an improved high speed rotary bone cutter comprising a drive shaft and a cutting head. The drive shaft has an elongated housing rotably mounted on the shaft. The housing has an enclosed fluid passageway around the shaft for the flow of cutting fluid. The passageway insulates the flowing fluid from the high rotational speed of the drive shaft.

Abstract: A process for depositing electrical charges on a dielectric surface by means of a high velocity jet of fluid which strikes the surface, flows over it and triboelectrically charges it, and then separates from the surface.