A holographic security or identification device (10) comprises an object, or a flexible substrate (12) configured to be conformable to a desired, curved shape; and a plurality of structures (14) formed on or in the object to have a desired curved configuration, or formed in or associated with the substrate and arranged to adopt a desired curved configuration when the substrate is conformed to a desired shape, wherein the plurality of structures (14) are configured to receive light (20) of a selected at least one wavelength or range of wavelengths and to produce, using the received light, a desired holographic image (22) for security or identification purposes when in the desired configuration.

Disclosed herein is a lens for a wearable projection system. The lens includes a holographic optical element embedded within the lens and covering a portion of the viewable area of the lens. The lens can be manufactured by filling a cavity in a lens blank with a photosensitive material and exposing the photosensitive material to a number of light beams to form the HOE.

A method and apparatus for in-line manufacture of a security document with a structured security element is provided in which a continuous web of document substrate is fed through a series of processing stations. The processing stations include a station for forming a structured security element in a radiation sensitive coating applied to the document substrate, and at least one station for applying at least one additional layer to the document substrate excluding the security element area. In a security document manufactured with the method or apparatus, the additional layer or layers have a combined thickness which is preferably substantially equal to the height of the structured security element or which differs from the height of the structured security element by a predetermined amount.

Systems, devices, and methods for holographic optical elements are described. A holographic optical element includes a first layer of holographic material and a second layer of holographic material. The first layer of holographic material includes a first hologram responsive to light in a first waveband and a second hologram responsive to light in a second waveband. The second layer of holographic material includes a third hologram responsive to light in a third waveband and may include a fourth hologram responsive to light in a fourth waveband. The first, second, third, and fourth wavebands are distinct and may comprise light of red, blue, green, and infrared wavelengths, respectively. Distribution of the three or four holograms on two layers of holographic material allows each hologram to have an index modulation of greater than 0.016, a diffraction efficiency of greater than 15%, and an angular bandwidth of greater than 12.

The invention relates to a sealed holographic medium comprising a layer construction containing a photopolymer layer and a sealing layer, to a process for producing the sealed holographic medium, to a kit of parts, to a layer construction for sealing and to the use thereof.

A main object of the present disclosure is to provide a hologram structure having excellent forgery preventability and designability. The present disclosure achieves the object by providing a hologram structure comprising: a hologram layer including a reflection type hologram forming region carrying a recorded phase type Fourier transform hologram that transforms an incident light from a point light source into a desired optical image; and a vapor deposition layer formed so as to come into contact with a concavo-convex surface of the reflection type hologram forming region of the hologram layer, and a size of the reflection type hologram forming region in plan view is in a range of 5 mm square or more and 50 mm square or less.

Disclosed herein is a lens for a wearable projection system. The lens includes a holographic optical element embedded within the lens and covering a portion of the viewable area of the lens. The lens can be manufactured by providing a first lens blank, affixing the HOE to a portion of the first lens blank, and forming a second lens blank on the first lens blank to embed the HOE between the lens blanks.

A method is provided. The method comprises: receiving incident light, from an object surface, on a top surface of a holographic optical field flattener (HOFF); transforming direction of light, with a hologram, if the light is incident on a portion of the HOFF at an angle equal to a non-zero field angle of the portion; and emitting transformed light from a bottom surface of the HOFF.

The present invention provides a means for suppressing an occurrence of a ghost by enhancing diffraction efficiency of a holographic optical element having a volume hologram recording layer. The present invention is a holographic optical element including: a volume hologram recording layer containing a photopolymer; and at least one adjacent layer which is in contact with the volume hologram recording layer and contains a resin, wherein a diffraction grating is formed so as to extend from the volume hologram recording layer to the adjacent layer.

A method includes obtaining a first optical assembly including a first optical element and a first flexible membrane. The first optical element has a first optical element surface and a second optical element surface that is opposite to the first optical element surface. The first flexible membrane has a first membrane surface and a second membrane surface that is opposite to the first membrane surface. The first optical element is a geometric phase optical element or a polarization volume hologram optical element. The second optical element surface of the first optical element is coupled with at least a first portion of the first membrane surface of the first flexible membrane. The method also includes coupling the first optical element with the first flexible membrane attached thereto to a target substrate. Also disclosed is an optical assembly comprising the first optical element and the first flexible membrane.