US4942102A — Holographic optical elements having a reflection …

Claim 1

Independent Claim 133 words

A holographic optical element comprising a transparent polymeric film containing a reflection hologram, said film having a refractive index modulation greater than approximately 0.001 and being formed by exposing to coherent light a composition consisting essentially of: (a) approximately 25 to 90% of a polymeric binder selected from the group consisting of polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl formal, interpolymers containing major segments thereof, and mixtures thereof; (b) approximately 5 to 60% of an ethylenically unsaturated liquid monomer containing at least one phenyl, biphenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic group containing up to three aromatic rings, chlorine or bromine moiety; (c) approximately 0 to 25% of a plasticizer; and (d) approximately 0.1 to 10% of a photoinitiator system activatable by actinic radiation wherein said percentages are weight percentages based on total film weight.

Claim 2

Dependent Claim 133 words

A holographic optical element comprising a transparent polymeric film containing a reflection hologram, said film having a refractive index modulation greater than approximately 0.001 and being formed by exposing to coherent light a composition consisting essentially of: (a) approximately 25 to 90% of a polymeric binder selected from the group consisting of polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl formal, interpolymers containing major segments thereof, and mixtures thereof; (b) approximately 5 to 60% of an ethylenically unsaturated liquid monomer containing at least one phenyl, biphenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic group containing up to three aromatic rings, chlorine or bromine moiety; (c) approximately 0 to 25% of a plasticizer; and (d) approximately 0.1 to 10% of a photoinitiator system activatable by actinic radiation wherein said percentages are weight percentages based on total film weight.

Claim 3

Dependent Claim 17 words

The element of claim 1 wherein the film has a reflection efficiency of at least approximately 15%.

Claim 4

Dependent Claim 10 words

The element of claim 2 mounted on a transparent substrate.

Claim 5

Dependent Claim 26 words

The element of claim 1 wherein said film has a thickness of approximately 1 to 100 micrometers and a refractive index modulation greater than approximately 0.005.

Claim 6

Dependent Claim 17 words

The element of claim 4 wherein said film has a reflection efficiency of at least approximately 70%.

Claim 7

Dependent Claim 40 words

The element of claim 1 wherein the ethylenically unsaturated monomer is a liquid selected from the group consisting of phenoxyethyl acrylate, phenol ethoxylate monoacrylate, the di(2-acryloxyethyl) ether of bisphenol-A, ethoxylated bisphenol-A diacrylate, 2-(1-naphthyloxy) ethyl acrylate, ortho-biphenyl methacrylate, and mixtures thereof.

Claim 8

Dependent Claim 74 words

The element of claim 1 containing a plasticizer selected from the group consisting of tris(2-ethylhexyl)phosphate, glyceryl tributyrate, and a compound having the general formula: ##STR2## wherein R 1 and R 2 each is an alkyl group of 1 to 10 carbon atoms, R 3 is H or an alkyl group of 8 to 16 carbon atoms, R 4 is H or CH 3 , x is 1-4, y is 2-20, and z is 1-20.

Claim 9

Dependent Claim 36 words

The element of claim 7 wherein the plasticizer is selected from the group consisting of triethylene glycol dicaprylate, triethylene glycol bis(2-ethylhexanoate), diethyl adipate, dibutyl adipate, tetraethylene glycol diheptanoate, diburyl suberate, diethyl sebacate, tris(2-ethylhexyl)phosphate, and glyceryl tributyrate.

Claim 10

Dependent Claim 15 words

The element of claim 1 wherein the composition contains up to approximately 5% optional ingredients.

Claim 11

Dependent Claim 54 words

The element of claim 1 wherein the components in said composition are present in the following approximate weight ranges: binder, 45 to 75%; monomer, 15 to 50%; plasticizer, 0 to 15%; initiator, 1 to 5%; and optional components, 0 to 4%; and said film has a refractive index modulation of at least approximately 0.005.

Claim 12

Dependent Claim 17 words

The element of claim 10 wherein said film has a thickness of approximately 1 to 100 micrometers.

Claim 13

Dependent Claim 17 words

The element of claim 11 wherein the film has a reflection efficiency of at least approximately 70%.

Claim 14

Dependent Claim 18 words

The element of claim 10 wherein the film has a refraction index modulation of at least approximately 0.01.

Claim 15

Dependent Claim 138 words

In a process for forming a reflection hologram wherein a reference beam of coherent actinic radiation and an object beam of the same coherent actinic radiation enter a layer of recording medium from opposite sides to create an interference pattern in the medium that forms the hologram, the improvement wherein the medium is a photopolymerizable film layer consisting essentially of: (a) a polymeric binder selected from the group consisting of polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl formal, interpolymers containing major segments thereof, and mixtures thereof; (b) an ethylenically unsaturated liquid monomer containing at least one phenyl, biphenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic group containing up to three aromatic rings, chlorine or bromine moiety; and (c) a photoinitiator system activatable by the actinic radiation and the resulting imaged medium has a refractive index modulation of at least approximately 0.001.

Claim 16

Dependent Claim 138 words

In a process for forming a reflection hologram wherein a reference beam of coherent actinic radiation and an object beam of the same coherent actinic radiation enter a layer of recording medium from opposite sides to create an interference pattern in the medium that forms the hologram, the improvement wherein the medium is a photopolymerizable film layer consisting essentially of: (a) a polymeric binder selected from the group consisting of polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl formal, interpolymers containing major segments thereof, and mixtures thereof; (b) an ethylenically unsaturated liquid monomer containing at least one phenyl, biphenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic group containing up to three aromatic rings, chlorine or bromine moiety; and (c) a photoinitiator system activatable by the actinic radiation and the resulting imaged medium has a refractive index modulation of at least approximately 0.001.

Claim 17

Dependent Claim 37 words

The process of claim 14 wherein the liquid monomer is selected from the group consisting of phenoxyethyl acrylate, phenol ethoxylate monoacrylate, the di(2-acryloxyethyl) ether of bisphenol-A, ethoxylated bisphenol-A diacrylate, 2-(1-naphthyloxy) ethyl acrylate, ortho-biphenyl methacrylate, and mixtures thereof.

Claim 18

Dependent Claim 81 words

The process of claim 14 in which a plasticizer is also present, which plasticizer is selected from the group consisting of tris(2-ethylhexyl)phosphate, glyceryl tributyrate, and a compound having the general formula: ##STR3## wherein R 1 and R 2 each is an alkyl group of 1 to 10 carbon atoms, R 3 is H or an alkyl group of 8 to 16 carbon atoms, R 4 is H or CH 3 , x is 1-4, y is 2-20, and z is 1-20.

Claim 19

Dependent Claim 36 words

The process of claim 16 wherein the plasticizer is selected from the group consisting of triethylene glycol dicaprylate, triethylene glycol bis(2-ethylhexanoate), diethyl adipate, dibutyl adipate, tetraethylene glycol diheptanoate, diburyl suberate, diethyl sebacate, tris(2-ethylhexyl)phosphate, and glyceryl tributyrate.

Claim 20

Dependent Claim 22 words

The process of claim 16 in which said plasticizer is substituted for at least a portion or the liquid ethylenically unsaturated monomer.

Claim 21

Dependent Claim 23 words

The process of claim 14 wherein the solid photopolymerizable layer contains an added crosslinking monomer containing two or more terminal ethylenically unsaturated groups.

Claim 22

Dependent Claim 18 words

The process of claim 19 wherein the crosslinking monomer is diacrylate or dimethacrylate of a bisphenol-A epoxy adduct.

Claim 23

Dependent Claim 173 words

A process for forming a reflection hologram in a photopolymerizable film recording medium comprising: A. Projecting a reference beam of coherent actinic radiation on a first side of the recording medium which consists essentially of: (1) a polymeric binder selected from the group consisting of polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl formal, interpolymers containing major segments thereof and mixtures thereof; (2) an ethylenically unsaturated liquid monomer containing at least one phenyl, biphenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic group containing up to three aromatic rings, chlorine or bromine moiety; and (3) a photoinitiator system activatable by the actinic radiation; B. Concurrently projecting an object beam of the same coherent actinic radiation approximately in an opposite direction to the reference beam onto a second side of the photopolymerizable film so as to intersect with the reference beam in a plane within the film whereby a reflection hologram is formed; C. Irradiating the imaged photopolymerizable layer with uniform source of actinic radiation; said resulting imaged medium having a refractive index modulation of at least approximately 0.001.

Claim 24

Dependent Claim 173 words

A process for forming a reflection hologram in a photopolymerizable film recording medium comprising: A. Projecting a reference beam of coherent actinic radiation on a first side of the recording medium which consists essentially of: (1) a polymeric binder selected from the group consisting of polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl formal, interpolymers containing major segments thereof and mixtures thereof; (2) an ethylenically unsaturated liquid monomer containing at least one phenyl, biphenyl, phenoxy, naphthyl, naphthyloxy, heteroaromatic group containing up to three aromatic rings, chlorine or bromine moiety; and (3) a photoinitiator system activatable by the actinic radiation; B. Concurrently projecting an object beam of the same coherent actinic radiation approximately in an opposite direction to the reference beam onto a second side of the photopolymerizable film so as to intersect with the reference beam in a plane within the film whereby a reflection hologram is formed; C. Irradiating the imaged photopolymerizable layer with uniform source of actinic radiation; said resulting imaged medium having a refractive index modulation of at least approximately 0.001.

Claim 25

Dependent Claim 33 words

The process of claim 21 including the step, after step C, of treating the irradiated layer with a liquid enhancing agent to increase the medium refractive index modulation to at least approximately 0.005.

Claim 26

Dependent Claim 38 words

The process of claim 22 wherein the liquid enhancing agent contains an organic liquid selected from the group consisting of an alcohol, a ketone, an aldehyde, a glycol alkyl ether, an ester, a liquid monomer and mixtures thereof.

Claim 27

Dependent Claim 42 words

The process of claim 23 wherein the liquid enhancing agent is selected from the group consisting of 1-propanol, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, cyclohexanone, benzaldehyde, ethyl acetate, butyl benzoate, phenoxyethyl acrylate, phenol ethoxylate acrylate, ethoxylated bisphenol-A diacrylate, and mixtures thereof.

Claim 28

Dependent Claim 16 words

The process of claim 22 wherein the liquid enhancing agent contains a substantially inert liquid diluent.

Claim 29

Dependent Claim 23 words

The process of claim 22 wherein the liquid diluent is selected from the group consisting of water, inert hydrocarbon solvents, 1,2-dichloroethane, and trichlorotrifluoroethane.

Claim 30

Dependent Claim 16 words

The process of claim 23 wherein swelling agent is removed from the treated layer by evaporation.

Claim 31

Dependent Claim 18 words

The process of claim 22 including the step of sealing the liquid enhancing agent in the recording medium.

Claim 32

Dependent Claim 46 words

The process of claim 22 wherein the liquid enhancing agent is a monomer, and including the additional steps of contacting the irradiated recording medium with liquid monomer that is absorbed by the medium, removing excess monomer, and polymerizing the absorbed monomer by exposure to actinic radiation.

Claim 33

Dependent Claim 29 words

The process of claim 29 wherein said treatment with liquid monomer is performed after the medium has been heated to a temperature above 50° C. to enhance reflection efficiency.

Claim 34

Dependent Claim 49 words

The process of claim 22 including the step of heating the medium, after it has been exposed to coherent radiation to form a reflection hologram, to a temperature of at least approximately 50° C. for a sufficient period to enhance the refractive index modulation to at least approximately 0.005.

Claim 35

Dependent Claim 22 words

The process of claim 31 wherein the medium is heated to a temperature in the range of approximately 80° to 160° C.

Claim 36

Dependent Claim 15 words

The process of claim 32 wherein said thermal enhancement step is conducted after step C.

Claim 37

Dependent Claim 25 words

The process of claim 21 wherein the recording medium is preheated immediately prior to exposing the medium to coherent radiation during steps A and B.

Claim 38

Dependent Claim 17 words

The process of claim 34 wherein the recording medium is preheated to approximately 30° to 50° C.

Claim 39

Dependent Claim 22 words

The process of claim 21 wherein the solid recording medium also contains crosslinking monomer containing at least two terminal ethylenically unsaturated groups.

Claim 40

Dependent Claim 18 words

The process of claim 36 wherein the crosslinking monomer is diacrylate or dimethacrylate of a bisphenol-A epoxy adduct.

Claim 41

Dependent Claim 31 words

The process of claim 21 wherein the unsaturated monomer is phenoxyethyl acrylate, phenol ethoxylate monoacrylate, the di(2-acryloxyethyl) ether of bisphenol-A, ethoxylated bisphenol-A diacrylate, 2-(1-naphthyloxy) ethyl acrylate, ortho-biphenyl methacrylate, and mixtures thereof.

Claim 42

Dependent Claim 81 words

The process of claim 21 in which a plasticizer is also present, which plasticizer is selected from the group consisting of tris(2-ethylhexyl)phosphate, glyceryl tributyrate, and a compound having the general formula: ##STR4## wherein R 1 and R 2 each is an alkyl group of 1 to 10 carbon atoms, R 3 is H or an alkyl group of 8 to 16 carbon atoms, R 4 is H or CH 3 , x is 1-4, y is 2-20, and z is 1-20.

Claim 43

Dependent Claim 35 words

The process of claim 39 wherein the plasticizer is selected from the group consisting of triethylene glycol dicaprylate, triethyleneglycol bis(2-ethylhexanoate), diethyl adipate, dibutyl adipate, tetraethylene glycol diheptanoate, dibutyl suberate, diethyl sebacate, tris(2-ethylhexyl)phosphate, and glyceryl tributyrate.

Claim 44

Dependent Claim 20 words

The process of claim 39 in which said plasticizer is substituted for a portion of the liquid ethylenically unsaturated monomer.

Claim 45

Dependent Claim 16 words

The element of claim 1 wherein a solid monomer is also present with said liquid monomer.

Claim 46

Dependent Claim 49 words

The element of claim 42 wherein said solid monomer is selected from the group consisting of N-vinyl carbazole; 3,6-dibromo-9-vinyl carbazole; 2,4,6-tribromophenyl acrylate or methacrylate; pentachlorophenyl acrylate or methacrylate; 2-vinyl naphthalene; 2-naphthyl acrylate or methacrylate; 2-(2-naphthyloxy)ethyl acrylate or methacrylate; para-biphenyl methacrylate; t-butylphenyl methacrylate, the di-(2-acryloxyethyl)ether of tetrabromobisphenol-A and mixtures thereof.

Claim 47

Dependent Claim 36 words

The element of claim 42 wherein said liquid monomer is selected from the group consisting of phenoxyethyl acrylate; phenol ethoxylate acrylate; the di(2-acryloxyethyl ether) of bisphenol-A; ortho-biphenyl methacrylate; ethoxylated bisphenol-A diacrylate; 2-(1-naphthyloxy)ethyl acrylate, and mixtures thereof.

Claim 48

Dependent Claim 14 words

The element of claim 42 or 44 wherein said solid monomer is N-vinyl carbazole.

Claim 49

Dependent Claim 16 words

The process of claim 14 wherein a solid monomer is also present with said liquid monomer.

Claim 50

Dependent Claim 49 words

The process of claim 46 wherein said solid monomer is selected from the group consisting of N-vinyl carbazole; 3,6-dibromo-9-vinyl carbazole; 2,4,6-tribromophenyl acrylate or methacrylate; pentachlorophenyl acrylate or methacrylate; 2-vinyl naphthalene; 2-naphthyl acrylate or methacrylate; 2-(2-naphthyloxy)ethyl acrylate or methacrylate; para-biphenyl methacrylate; t-butylphenyl methacrylate, the di-(2-acryloxyethyl)ethyl of tetrabromobisphenol-A and mixtures thereof.

Claim 51

Dependent Claim 36 words

The process of claim 46 wherein said liquid monomer is selected from the group consisting of phenoxyethyl acrylate; phenol ethoxylate acrylate; the di(2-acryloxyethyl ether) of bisphenol-A; ortho-biphenyl methacrylate; ethoxylated bisphenol-A diacrylate; 2-(1-naphthyloxy)ethyl acrylate; and mixtures thereof.

Claim 52

Dependent Claim 14 words

The process of claim 46 or 48 wherein said solid monomer is N-vinyl carbazole.

Claim 53

Dependent Claim 16 words

The process of claim 21 wherein a solid monomer is also present with said liquid monomer.

Claim 54

Dependent Claim 49 words

The process of claim 50 wherein said solid monomer is selected from the group consisting of N-vinyl carbazole; 3,6-dibromo-9-vinyl carbazole; 2,4,6-tribromophenyl acrylate or methacrylate; pentachlorophenyl acrylate or methacrylate; 2-vinyl naphthalene; 2-naphthyl acrylate or methacrylate; 2-(2-naphthyloxy)ethyl acrylate or methacrylate; para-biphenyl methacrylate; t-butylphenyl methacrylate, the di-(2-acryloxyethyl)ether of tetrabromobisphenol-A, and mixtures thereof.

Claim 55

Dependent Claim 36 words

The process of claim 50 wherein said liquid monomer is selected from the group consisting of phenoxyethyl acrylate; phenol ethoxylate acrylate; the di-(2-acryloxytheyl ether) of bisphenol-A; ortho-biphenyl methacrylate; ethoxylated bisphenol-A diacrylate; 2-(1-naphthyloxy)ethyl acrylate; and mixtures thereof.

Claim 56

Dependent Claim 14 words

The process of claim 50 or 52 wherein said solid monomer is N-vinyl carbazole.

Claim 57

Dependent Claim 33 words

The process of claim 50 including the step, after step C, of treating the irradiated layer with a liquid enhancing agent to increase the medium refractive index modulation to at least approximately 0.005.

Claim 58

Dependent Claim 38 words

The process of claim 54 wherein the liquid enhancing agent contains an organic liquid selected from the group consisting of an alcohol, a ketone, an aldehyde, a glycol alkyl ether, an ester, a liquid monomer and mixtures thereof.

Claim 59

Dependent Claim 42 words

The process of claim 55 wherein the liquid enhancing agent is selected from the group consisting of 1-propanol, methanol, ethanol, 2-propanol, acetone, methyl ethyl ketone, cyclohexanone, benzaldehyde, ethyl acetate, butyl benzoate, phenoxyethyl acrylate, phenol ethoxylate acrylate, ethoxylated bisphenol-A diacrylate, and mixtures thereof.

Claim 60

Dependent Claim 16 words

The process of claim 54 wherein the liquid enhancing agent contains a substantially inert liquid diluent.

Claim 61

Dependent Claim 23 words

The process of claim 57 wherein the liquid diluent is selected from the group consisting of water, inert hydrocarbon solvents, 1,2-dichloroethane, and trichlorotrifluoroethane.

Claim 62

Dependent Claim 17 words

The process of claim 55 wherein excess enhancing agent is removed from the treated layer by evaporation.

Claim 63

Dependent Claim 18 words

The process of claim 54 including the step of sealing the liquid enhancing agent in the recording medium.

Claim 64

Dependent Claim 50 words

The process of claim 54 wherein the liquid enhancing agent is a monomer, and including the additional steps of contacting the irradiated recording medium with liquid monomer that is absorbed by the medium, drying the medium to remove excess monomer, and polymerizing the absorbed monomer by exposure to actinic radiation.

Claim 65

Dependent Claim 29 words

The process of claim 61 wherein said treatment with liquid monomer is performed after the medium has been heated to a temperature above 50° C. to enhance reflection efficiency.

Claim 66

Dependent Claim 49 words

The process of claim 50 including the step of heating the medium, after it has been exposed to coherent radiation to form a reflection hologram, to a temperature of at least approximately 50° C. for a sufficient period to enhance the refractive index modulation to at least approximately 0.005.

Claim 67

Dependent Claim 23 words

The process of claim 63 wherein the medium is heated to a temperature in the range of approximately 80° C. to 160° C.

Claim 68

Dependent Claim 15 words

The process of claim 64 wherein said thermal enhancement step is conducted after step C.

Claim 69

Dependent Claim 25 words

The process of claim 50 wherein the recording medium is preheated immediately prior to exposing the medium to coherent radiation during steps A and B.

Claim 70

Dependent Claim 18 words

The process of claim 66 wherein the recording medium is preheated to approximately 30° C. to 50° C.

Claim 71

Dependent Claim 22 words

The process of claim 50 wherein the solid recording medium also contains crosslinking monomer containing at least two terminal ethylenically unsaturated groups.

Claim 72

Dependent Claim 18 words

The process of claim 68 wherein the crosslinking monomer is diacrylate or dimethacrylate of a bisphenol-A epoxy adduct.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1993-07-16	1994-01-15	1994-07-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1997-07-16	1998-01-15	1998-07-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2001-07-16	2002-01-15	2002-07-17	$7700.00	Window Closed / Lapsed

Holographic optical elements having a reflection hologram formed in a photopolymer

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