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Straight-Line, Two-Dimensional Holographic Scanner

IP.com Disclosure Number: IPCOM000038505D
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Sincerbox, GT: AUTHOR

Abstract

Straight-line, two-dimensional scanning is achieved, as shown in Fig. 1, by using two holographic scanners, mounted on the same shaft and rotating together. (Alternately, the holograms are on opposite sides of the same substrate.) The lower hologram, Hl, is recorded with the proper reference beam angle (a=45.55 degrees) and an object beam angle, bi, that varies from facet to facet. The reconstructed beams resulting from illumination of each facet impinge on the upper hologram, Hu, at different radial locations. Each facet of the upper hologram is recorded with a reference beam corresponding to these different direc tions of illumination, but all with the same object beam direction, b=44.45 degrees.

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Straight-Line, Two-Dimensional Holographic Scanner

Straight-line, two-dimensional scanning is achieved, as shown in Fig. 1, by using two holographic scanners, mounted on the same shaft and rotating together. (Alternately, the holograms are on opposite sides of the same substrate.) The lower hologram, Hl, is recorded with the proper reference beam angle (a=45.55 degrees) and an object beam angle, bi, that varies from facet to facet. The reconstructed beams resulting from illumination of each facet impinge on the upper hologram, Hu, at different radial locations. Each facet of the upper hologram is recorded with a reference beam corresponding to these different direc tions of illumination, but all with the same object beam direction, b=44.45 degrees. Consequently, each facet (combination) has the proper incidence and diffraction angles that are necessary to create a straight scan line and are displaced radially to give separate scan lines, i.e., a two-dimensional raster pattern. As many scan lines are created as there are facets. As an example, the scan line separation, Dij, between two facets i and j is given by: Dij = h(tan Bi - tan Bj) / cos b (1) where: h = vertical separation of the holograms bi = diffraction angle from Hui bj = diffraction angle from Huj b = final diffraction angle (44.45 degrees) When we use Z1 degree increments about the nominal angle of 45 degrees (the increment gets smaller as Bi increases, and larger as it decreases to maintain constant...