An optical element of the present disclosure includes a hologram layer, a resin substrate to which the hologram layer is adhered, and a holder portion that supports the resin substrate and has a thermal expansion coefficient smaller than that of the resin substrate. One of the holder portion and the resin substrate includes a contact surface along an axis extending in a plate thickness direction of the resin substrate, and the other of the holder portion and the resin substrate includes a pressing surface that presses the contact surface.

A backlight device having a light guide, a first holographic optical element and a second holographic element are provided. The light guide plate guides light emitted by a light source towards the first holographic optical element. The first holographic optical element, which has a multi-layered structure, is provided on a first side of the light guide plate and reflects the light according to the wavelength ranges based on the characteristics of the multi-layered structure. The second holographic optical element, which concentrates light reflected by the first holographic optical element onto at least two points is provided on a second side of the light guide plate perpendicular to the first side.

A liquid crystal laminate includes a substrate including a first diffraction surface and a second base material surface and having optical transparency, a metal layer located on a part of the first diffraction layer, an adhesion layer located on a part of the second base material layer and made of a photocured resin, and liquid crystal layer located on a surface of the adhesion layer at a side opposite to the contact surface of the substrate.

An optical device including a first rigid substrate, a flexible holographic optical element, a transparent flexible material having a variable shear transmission property across an in-plane direction of the flexible holographic optical element, and a second rigid substrate, where the flexible holographic optical element and the transparent flexible material are located between the first and second rigid substrates, where the variable shear transmission property of the transparent flexible material transmits variable amounts of a shear force applied to the first or second rigid substrates across the in-plane direction of the flexible holographic optical element.

An optical device including a first rigid substrate, a flexible holographic optical element, a transparent flexible material having a variable shear transmission property across an in-plane direction of the flexible holographic optical element, and a second rigid substrate, where the flexible holographic optical element and the transparent flexible material are located between the first and second rigid substrates, where the variable shear transmission property of the transparent flexible material transmits variable amounts of a shear force applied to the first or second rigid substrates across the in-plane direction of the flexible holographic optical element.

A backlight device having a light guide, a first holographic optical element and a second holographic element are provided. The light guide plate guides light emitted by a light source towards the first holographic optical element. The first holographic optical element, which has a multi-layered structure, is provided on a first side of the light guide plate and reflects the light according to the wavelength ranges based on the characteristics of the multi-layered structure. The second holographic optical element, which concentrates light reflected by the first holographic optical element onto at least two points is provided on a second side of the light guide plate perpendicular to the first side.

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.

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.

To provide an authentication device and method for a security medium including a reflective volume hologram having a light source disposed on the front surface side of the reflective volume hologram so that light emitted therefrom is incident on the reflective volume hologram, a first observation device disposed in a pre-designed diffraction direction of the reflective volume hologram, and a second observation device disposed in a direction other than the pre-designed diffraction direction of the reflective volume hologram. Light including a pre-designed diffraction wavelength is emitted from the light source to be incident on the reflective volume hologram, and when the light amount observed in the first observation device is larger in the diffraction wavelength than in other wavelengths, and the light amount observed in the second observation device is smaller in the diffraction wavelength than in other wavelengths, it is determined that the reflective volume hologram is genuine.

To provide an authentication device and method for a security medium including a reflective volume hologram having a light source disposed on the front surface side of the reflective volume hologram so that light emitted therefrom is incident on the reflective volume hologram, a first observation device disposed in a pre-designed diffraction direction of the reflective volume hologram, and a second observation device disposed in a direction other than the pre-designed diffraction direction of the reflective volume hologram. Light including a pre-designed diffraction wavelength is emitted from the light source to be incident on the reflective volume hologram, and when the light amount observed in the first observation device is larger in the diffraction wavelength than in other wavelengths, and the light amount observed in the second observation device is smaller in the diffraction wavelength than in other wavelengths, it is determined that the reflective volume hologram is genuine.