An optical system comprises an imaging holographic optical element, which produces a floating hologram. An upstream light-forming holographic optical element causes spectral filtering of the light.

A polarization diffraction element comprising including a film including a liquid crystalline material having photosensitivity, the film having at least one hologram recorded therein, and thereby having a property as a fork-shaped polarization grating having an anisotropic structure in which an optical axis continuously rotates toward a direction of a grating vector.

The invention relates to a method for producing a holographic optical element by providing a recording stack comprising at least one recording element laminated on at least one supporting element, irradiating at least a part of the recording stack with at least one recording beam in an irradiating step, wherein during the irradiating step, the recording stack bends, providing a bending deviation threshold for the recording stack, and adjusting at least one first process parameter such that an expected maximum bending deviation of the recording stack does not exceed the bending deviation threshold, wherein the at least one first process parameter influences the bending behaviour of the recording stack during the irradiating step.

The invention provides an exposure method of a holographic grating and an exposure light path. The exposure method includes: (1) determining initial positions (C, D) of the two exposure light sources (S1, S2); (2) calculating imaging quality parameters of the grating; (3) setting a compensating mirror (A1) in the initial light path; (4) adjusting a position of the exposure light source (S1) to a new position (D1) according to a position of the compensating mirror (A1); (5) calculating imaging quality parameters of the grating; (6) judging whether the imaging quality parameters in the step (5) and the imaging quality parameters in the step (2) are equal, and if yes, using the new position (D1) as a final position of the exposure light source (S1). The exposure method and exposure light path may effectively solve a problem of a much too close distance between exposure light sources.

In a process of manufacturing the volume holographic element, a holographic material layer is irradiated with reference light from the side of a second substrate in the oblique direction, and the holographic material layer is vertically irradiated with object light from the side of a first substrate in an interference exposure process. Since a first translucent anti-reflective layer is formed on the first surface of the first substrate, it is difficult that situation in which the reference light is reflected in the first surface in the oblique direction occurs. In addition, since a second translucent anti-reflective layer is formed on the second surface of the second substrate, it is difficult that a situation in which the object light is reflected in the second surface occurs.

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.

A laser beam (L50) is reflected by a light beam scanning device (60) and irradiated onto a hologram recording medium (45). On the hologram recording medium (45), an image (35) of a linear scatter body is recorded as a hologram by using reference light that converges on a scanning origin (B). The light beam scanning device (60) bends the laser beam (L50) at the scanning origin (B) and irradiates the laser beam onto the hologram recording medium (45). At this time, by changing a bending mode of the laser beam with time, an irradiation position of the bent laser beam (L60) on the hologram recording medium (45) is changed with time. Diffracted light (L45) from the hologram recording medium (45) produces a reproduction image (35) of the linear scatter body on a light receiving surface (R) of the stage 210. When an object is placed on the light receiving surface (R), a line pattern is projected by hologram reproduction light, so that the projected image is captured and a three-dimensional shape of the object is measured.

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.

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.

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.