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 for manufacturing a security element includes forming a first layer from a transparent material, forming a first holographic surface structure on the first layer, metallizing the first layer to form a first metal layer, forming a second layer from a radiation-sensitive polymer, forming a second holographic surface structure on the second layer, metallizing the second layer to form the second metal layer, forming a pattern of a coating on the second metal layer in which the pattern includes regions covered by the coating and regions uncovered by the coating, removal of the metal in regions of the second metal layer which are uncovered by the coating through de-metallization, exposing the de-metallized regions of the second layer to light or radiation, and removal of the metal in regions of the first metal layer that are not covered by the second layer, through de-metallization.

A fingerprint sensor integrated display using a holographic optical element and a recording and reconstruction method of the holographic optical element are disclosed. The fingerprint sensor integrated display includes a display panel on which an input image is displayed, a transparent substrate disposed on the display panel, and a light entering element configured to irradiate light from a light source onto the transparent substrate. A particular type of visual information is reconstructed through a holographic element at a location of the light entering element.

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.

A method and system for forming a holographic structure in a material. The holographic structure is configured to project a selected target image in the far field under illumination of the holographic structure by a laser. The method calculates a modified design for the holographic structure that encodes a unique identifier within the holographic structure for projecting the target image. The method modifies the material by mapping features corresponding to the modified design into the material so as to form the holographic structure. A basic check of the authenticity of the material is performed by checking whether a projected replica of the target image is as expected. A more detailed check of the authenticity of the material is performed by directly inspecting the features in the holographic structure.

A mobile hologram apparatus is disclosed. An example apparatus includes a sheet folded along preformed creases into a pyramid structure configured to be actuated between a compressed state and an uncompressed state. The pyramid structure has a base section and a top section connected by four side sections. The pyramid structure in the compressed state has a height that is less than 1/10th the height of the pyramid structure in the uncompressed state. The apparatus also includes an elastic band connected to a perimeter of the base section of the pyramid structure and configured to cause the pyramid structure to self-actuate from the compressed state to the uncompressed state.

A system for making a holographic medium for use in generating light patterns for eye tracking includes a light source configured to provide light and a beam splitter configured to separate the light into a first portion of the light and a second portion of the light that is spatially separated from the first portion of the light. The system also includes a first set of optical elements configured to transmit the first portion of the light for providing a first wide-field beam onto an optically recordable medium and one or more diffractive optical elements configured to receive the second portion of the light and project a plurality of separate light patterns onto the optically recordable medium for forming the holographic medium.

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 are devices and methods to provide a holographic optical element (HOE) having a modified shape and a structural attribute. At least one wavefront may be used to cause a first structure change in a material, used for the HOE, in a first shape. The material used for the HOE may be changed from the first shape to the modified shape to cause a second structure change in the material. The structural attribute in the material may be provided from a combination of the first structure change and the second structure change.

The present disclosure provides a holographic display device including: a first substrate and a second substrate disposed opposite to each other, wherein a display screen disposed on the first substrate, and the display surface of the display screen faces the second substrate; and four trapezoidal holographic plates, wherein the upper side edge of each trapezoidal holographic plate is movably connected to the first substrate, the lower side edge of each trapezoidal holographic plate is movably connected to the second substrate; wherein the holographic display device has a first state and a second state, wherein in the first state, four trapezoidal holographic plates enclose a four-sided prismoid structure and are supported between the first substrate and the second substrate; in the second state, the first substrate and the second substrate are stacked, and four trapezoidal holographic plates are unfolded to be in the same plane and stacked between the first substrate and the second substrate. The holographic display device provided by the present disclosure can realize miniaturization and improve portability.