Multicolor hologram and method for forming same
AssigneeMinnesota Mining and Manufacturing Company
InventorTruman F. Kellie
Life of this patent
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Abstract
A hologram capable of reconstructing a multicolor three-dimensional image is formed in which a plurality of standing wave interference fringe patterns corresponding to primary color components of a multicolored object are spatially multiplexed as a relief pattern on a surface of the hologram. A permanent optical density image of the spatially multiplexed fringe patterns is first formed on a panchromatic photographic plate. The plate is overcoated with a photoresist layer, back-exposed to contact-print the optical densit image onto the photoresist layer, after which the layer is processed to form the surface relief pattern.
Claims12
A method for forming a surface relief holographic article suitable for the holographic reconstruction of a three-dimensional multicolor image of an original three-dimensional multicolored object, comprising the steps of
- (a) directing a first pair of beams including a mutually coherent reference beam and object beam having information corresponding to one color component of said multicolored three-dimensional object modulated thereon against a first group of small areas distributed along a surface of a photographic medium to form a latent image of a first standing wave interference fringe pattern corresponding to said one color component,
- (b) directing an additional pair of mutually coherent beams including a reference beam and an object beam having information corresponding to an additional color component of said object modulated thereon against a second group of small areas distributed along said medium, which second group of areas is displaced from and distinct from said first group, to form a latent image of a second standing wave interference fringe pattern corresponding to said additional color component,
- (c) processing said medium to form a holographic article which includes a permanent image of said fringe patterns as regions of varying optical density,
- (d) positioning a positive photoresist layer in intimate optical contact with the processed medium,
- (e) directing light through the processed medium and onto the photoresist layer to provide in said layer a latent image of said permanent image, and
- (f) processing the photoresist layer to provide a said surface relief holographic article which comprises a substantially homogeneous polymeric sheet having formed on a surface thereof an optically detectable relief pattern corresponding to said fringe patterns, whereby a three-dimensional multicolor reconstruction of said object may be obtained by directing white light through a multicolor mask and onto the article, said mask being positioned in registration with the article such that a given color in the mask is adjacent portions of the hologram corresponding to that color.
Dependencies are inferred from the claim text.