High efficiency holograms by multiple-layer holography

Claim 1

A method of forming a holographic device, said method comprising the steps of: (a) forming a first hologram on a major surface of a substrate with following steps: (i) first, providing a photo-sensitive layer comprising photoreactive material and photosensitive material, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photo-sensitive layer to create a latent image, and (b) desensitizing by removing said photoreactive material from said photosensitive material from said first hologram to prevent interaction with a second subsequently formed hologram; (c) forming the second subsequently formed hologram conterminous with said first hologram, with the following steps: (i) first, providing a photosensitive layer on said first hologram, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (d) processing together said first and second holograms to fully develop the holographic image and to achieve a predetermined fringe configuration in the first and second holograms, so that the holograms of said device are bonded together absent an adhesive layer between said first and second holograms.

Claim 2

A method of forming a holographic device, said method comprising the steps of: (a) forming a first hologram on a major surface of a substrate with following steps: (i) first, providing a photo-sensitive layer comprising photoreactive material and photosensitive material, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photo-sensitive layer to create a latent image, and (b) desensitizing by removing said photoreactive material from said photosensitive material from said first hologram to prevent interaction with a second subsequently formed hologram; (c) forming the second subsequently formed hologram conterminous with said first hologram, with the following steps: (i) first, providing a photosensitive layer on said first hologram, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (d) processing together said first and second holograms to fully develop the holographic image and to achieve a predetermined fringe configuration in the first and second holograms, so that the holograms of said device are bonded together absent an adhesive layer between said first and second holograms.

Claim 6

A method of forming a holographic device, said method comprising the steps of: (a) forming a first hologram on a major surface of a substrate with the following steps: (i) first, providing a photosensitive layer comprising photoreactive material and photosensitive material, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (b) desensitizing by removing said photoreactive material from said photosensitive material from said first hologram to prevent interaction with a second subsequently formed hologram; (c) forming the second subsequently formed hologram conterminous with the first hologram, with the following steps: (i) first, providing a photosensitive layer on said first hologram, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (d) desensitizing by removing said photoreactive material from said photosensitive material from said second hologram to prevent interaction with a third subsequently formed hologram; (e) forming the third subsequently formed hologram conterminous with the second hologram, with the following steps: (i) first, providing a photosensitive layer on said second hologram, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (f) processing together said first, second and third holograms to fully develop the holographic image and to achieve a predetermined fringe configuration in the holograms, so that the holograms of said device are bonded together absent an adhesive layer between the respective holograms.

Claim 7

A method of forming a holographic device, said method comprising the steps of: (a) forming a first hologram on a major surface of a substrate with the following steps: (i) first, providing a photosensitive layer comprising photoreactive material and photosensitive material, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (b) desensitizing by removing said photoreactive material from said photosensitive material from said first hologram to prevent interaction with a second subsequently formed hologram; (c) forming the second subsequently formed hologram conterminous with the first hologram, with the following steps: (i) first, providing a photosensitive layer on said first hologram, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (d) desensitizing by removing said photoreactive material from said photosensitive material from said second hologram to prevent interaction with a third subsequently formed hologram; (e) forming the third subsequently formed hologram conterminous with the second hologram, with the following steps: (i) first, providing a photosensitive layer on said second hologram, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (f) processing together said first, second and third holograms to fully develop the holographic image and to achieve a predetermined fringe configuration in the holograms, so that the holograms of said device are bonded together absent an adhesive layer between the respective holograms.

Claim 8

A method of forming a holographic device, said method comprising the steps of: (a) forming a first hologram on a major surface of a substrate with the following steps: (i) first, providing a photo-sensitive layer, comprising photoreactive material and photosensitive material, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (b) desensitizing by removing said photoreactive material from said photosensitive material from said first hologram to prevent interaction with an adjacent subsequently formed holgram; and (c) forming a plurality of subsequently formed holograms conterminous with the first hologram, with the following steps: (i) first, providing a photosensitive layer on a last prior hologram, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (d) desensitizing each hologram by removing said photoreactive material from said photosensitive material from said hologram to prevent interaction with the next adjacent subsequently formed hologram; (e) processing together all holograms to fully develop the holographic image and to achieve a predetermined fringe configuration in the holograms, so that the holograms of said device are bonded together absent an adhesive layer between the respective holograms.

Claim 9

A method of forming a holographic device, said method comprising the steps of: (a) forming a first hologram on a major surface of a substrate with the following steps: (i) first, providing a photo-sensitive layer, comprising photoreactive material and photosensitive material, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (b) desensitizing by removing said photoreactive material from said photosensitive material from said first hologram to prevent interaction with an adjacent subsequently formed holgram; and (c) forming a plurality of subsequently formed holograms conterminous with the first hologram, with the following steps: (i) first, providing a photosensitive layer on a last prior hologram, (ii) second, drying said photosensitive layer to a predetermined moisture content, (iii) third, exposing said photosensitive layer to create a latent image, and (d) desensitizing each hologram by removing said photoreactive material from said photosensitive material from said hologram to prevent interaction with the next adjacent subsequently formed hologram; (e) processing together all holograms to fully develop the holographic image and to achieve a predetermined fringe configuration in the holograms, so that the holograms of said device are bonded together absent an adhesive layer between the respective holograms.

Claim 10

A method of forming a multi-layer holographic device, said method comprising the steps of: (a) coating a major surface of a substrate with a first photosensitive gelatin layer; (b) drying said first photosensitive-gelatin layer to a predetermined moisture content; (c) exposing said first photosensitive layer to form a first hologram having a first holographic fringe configuration formed therein; (d) removing ammonium dichromate from said first gelatin layer so as to desensitize said layer; (e) partially dehydrating said first gelatin layer in an alcohol bath to partially develop the first holographic image; (f) heating said first gelatin layer for a predetermined amount of time so as to form within the hologram a desired fringe spacing which reflects light at a peak wavelength for which light diffraction is sought, and to surface harden said first gelatin layer; (g) coating at a temperature of less than about 50° C., a major surface of said first gelatin layer with a second photosensitive layer so that the light-diffracting effects of the first hologram are substantially erased; (h) exposing said second photosensitive layer to form a second hologram having a second holographic fringe configuration formed therein; and (i) processing together said first and second layers to fully develop the holographic image and to achieve a predetermined fringe configuration in the first and second holograms.

Claim 11

A method of forming a multi-layer holographic device, said method comprising the steps of: (a) coating a major surface of a substrate with a first photosensitive gelatin layer; (b) drying said first photosensitive-gelatin layer to a predetermined moisture content; (c) exposing said first photosensitive layer to form a first hologram having a first holographic fringe configuration formed therein; (d) removing ammonium dichromate from said first gelatin layer so as to desensitize said layer; (e) partially dehydrating said first gelatin layer in an alcohol bath to partially develop the first holographic image; (f) heating said first gelatin layer for a predetermined amount of time so as to form within the hologram a desired fringe spacing which reflects light at a peak wavelength for which light diffraction is sought, and to surface harden said first gelatin layer; (g) coating at a temperature of less than about 50° C., a major surface of said first gelatin layer with a second photosensitive layer so that the light-diffracting effects of the first hologram are substantially erased; (h) exposing said second photosensitive layer to form a second hologram having a second holographic fringe configuration formed therein; and (i) processing together said first and second layers to fully develop the holographic image and to achieve a predetermined fringe configuration in the first and second holograms.