Provided is a photopolymer composition that may exhibit low volume shrinkage during holographic recording and may prevent a photosensitive dye from remaining unbleached after holographic recording.

A main object of the present invention is to provide a method of producing a volume hologram laminate which can regenerate a hologram image in an arbitrary wavelength by a simple process. To attain the object, the present invention provides a method of producing a volume hologram laminate using a volume hologram forming substrate which comprises: a substrate, a volume hologram layer formed on the substrate and containing a photopolymerizable material, a resin layer, formed on the substrate so as to contact to the volume hologram layer, containing a resin and a polymerizable compound, characterized in that the producing method comprises processes of: a hologram recording process to record a volume hologram to the volume hologram layer, a substance transit process of transiting the polymerizable compound to the volume hologram layer, and an after-treatment process of polymerizing the polymerizable compound.

The invention relates to a photopolymer formulation comprising specific aromatic glycol ethers as writing monomers, matrix polymers and a photoinitiator. The invention further provides an unexposed holographic medium obtainable using an inventive photopolymer formulation, and an exposed holographic medium obtainable by exposing a hologram into an inventive unexposed holographic medium. The invention likewise provides a visual display comprising an inventive exposed holographic medium, for the use of an inventive exposed holographic medium for production of chip cards, identification documents, 3D images, product protection labels, labels, banknotes or holographic optical elements, and specific aromatic glycol ethers.

A holographic recording medium composition comprising components (a) to (d) below, wherein an amount of allophanate bond units contained in the component (a) relative to a total weight of the components (a) and (b) is 6.510.sup.4 mol/g or more: component (a): an isocyanate group-containing compound; component (b): an isocyanate-reactive functional group-containing compound; component (c): a polymerizable monomer; and component (d): a photopolymerization initiator.

A method for producing an optical element, wherein a hologram recording medium having a recording layer containing a polymerizable compound and a photopolymerization initiator is subjected to multiple recording exposure of a hologram under conditions where average exposure intensity based on the following formula (1) is 6 mW/cm.sup.2 or more.

[00001]$\begin{array}{cc}\mathrm{Average}\mathrm{exposure}\mathrm{intensity}=\frac{{.Math.}_{i=1}^m\left({\mathrm{ET}}_i{\mathrm{EPW}}_i\right)}{{.Math.}_{i=1}^m\left({\mathrm{ET}}_i+{\mathrm{EIT}}_{i-1}\right)}& \left(1\right)\end{array}$

(In the formula (1), ET.sub.i is a single exposure time, which indicates exposure time (seconds) per multiple recording exposure. EPW.sub.i is exposure light intensity, which indicates total light intensity (mW/cm.sup.2) of reference light and object light. EIT.sub.i-1 is exposure interval time, which indicates time (seconds) between one recording exposure and another recording exposure in the multiple recording exposure. m is a natural number indicating a total number of multiplexes. With the proviso that when i=1, EIT.sub.i-1 is treated as zero.)

The invention relates to polycarbonate-based or copolycarbonate-based security documents and/or documents of value which contain at least one hologram integrated in the card body, and to a method for producing such security documents and/or documents of value.

The present disclosure relates to a method for producing a beam shaping holographic optical element, which is configured to generate diffracted beams configured to reconstruct an image of a diffusor irrespectively of the point of impact of a pencil of light on the beam shaping holographic optical element, comprising providing a recording element, providing a master element comprising a particular pattern, forming a recording stack comprising the recording element and the master element such that the master element is arranged to the recording element in a closed-copy distance, irradiating at least a part of the recording stack with a reconstruction beam, irradiating at least a part of the recording stack with a reference beam, wherein at least one of the reconstruction beam or reference beam penetrates the master element to record the pattern of the master element onto the recording element.

The disclosure relates to photopolymer compositions including a) matrix polymers, b) writing monomers, c) at least one photoinitiator system, d) optionally at least one non-photopolymerizable component, e) optionally catalysts, radical stabilizers, solvents, additives, and other auxiliary agents and/or admixtures, where the at least one photoinitiator system c) consists of at least one dye and at least one coinitiator, at least one of the dyes has a structure according to formula (II), and the at least one coinitiator has a calculated oxidation potential which is ascertained according to the formula (1).

Improvements to gratings for use in waveguides and methods of producing them are described herein. Deep surface relief gratings (SRGs) may offer many advantages over conventional SRGs, an important one being a higher S-diffraction efficiency. In one embodiment, deep SRGs can be implemented as polymer surface relief gratings or evacuated periodic structures (EPSs). EPSs can be formed by first recording a holographic polymer dispersed liquid crystal (HPDLC) periodic structure. Removing the liquid crystal from the cured periodic structure provides a polymer surface relief grating. Polymer surface relief gratings have many applications including for use in waveguide-based displays.

The invention relates to a photopolymer composition including a) matrix polymers, b) writing monomers, c) at least one photoinitiator system, d) optionally at least one non-photopolymerisable component, e) optionally catalysts, radical stabilisers, solvents, additives and other auxiliary and/or additional materials. The at least one photoinitiator system c) consists of at least one colouring agent and at least one coinitiator. At least one of the colouring agents has a structure according to formula (I) and the at least one coinitiator has a calculated oxidation potential (formula II), determined according to the below formula (1) via the quantum mechanical calculation of Gibbs energies at 298 K in the basic state and the oxidised state of the coinitiator, in particular the triaryl (alkyl) borate after geometry optimisation, involving conformer energy minimisation using the AMI force field, followed by an ab-initio conformer energy calculation based on the previously determined molecular geometry coordinates, in the solvent, acetonitrile, with a solvent field correction according to the PCM method, is in the range of 1.16 V to 1.37 V relative to the saturated calomel electrode (SCE) in acetonitrile (formula III).