A display method lets a display beam to propagate in a transparent substrate while internally reflected repeatedly and lets the display beam partly emit out of the transparent substrate every time the display beam is internally reflected, thereby emitting display beams from almost entirety of a surface of the transparent substrate. The display beam is produced holographically. A display apparatus includes a spatial phase modulator that produces a display beam, a transparent substrate in which the display beam is internally reflected repeatedly to propagate in it, and a splitter that lets the display beam partly emit out of the transparent substrate every time the display beam is internally reflected.

Holograms are generated using a rotatable transparent cylinder and a coherent light source placed inside or outside of such cylinder to record a hologram in a photosensitive film having a reflective film on one side. Recording is done in continuous mode while cylinder is rotating and photosensitive film is translating underneath in contact with cylinder due to friction forces provided by a layer of sticky polymer.

A device and method for recording and reproducing holographic information, and a display apparatus are disclosed. The device for recording holographic information comprises an electro-optical regulating element, which is arranged in a light path between an object to be reproduced and a recording medium, receives an object beam scattered by the object to be reproduced, and regulates an outgoing direction and a focal distance of the object beam to irradiate the recording medium. The recording medium is configured to receive the reference beam from the light source and the object beam regulated by the electro-optical regulating element. The reference beam and the object beam form information relevant with the object to be reproduced in the recording medium. By regulating the outgoing direction and focal distance of beam with the electro-optical regulating element, it is unnecessary to rotate the recording medium for recording and reproducing the holographic information.

A holographic 3D recording device includes: a photorefractive crystal and a microlens array. The microlens array includes an array face and a side face. The microlens array is provided in a light path from an object to be photographed to the photorefractive crystal such that first light of object emitted through a diffuse reflection of the object to be photographed passes through the array face of the microlens array and becomes second light of object that is emitted to the photorefractive crystal. The photorefractive crystal is configured to receive the second light of object emitted by the microlens array and reference light, respectively, and save therein an interference fringe formed by the reference light and the second light of object. The first light of object and the reference light are coherent light.

A backlight unit includes: a light source unit which outputs coherent light; a first reflection unit including a parabolic mirror; a second reflection unit facing the first reflection unit and including a flat mirror; and a holographic optical element which changes a path of incident light, where a reflection surface of the second reflection unit forms an acute angle with an light incident surface of the holographic optical element, and the coherent light output from the light source unit sequentially passes the first reflection unit, the second reflection unit, and the holographic optical element.

A manufacturing method of an optical element applied to a miniature microscope includes the steps of: emitting a signal light and a reference light to an optical material; and forming a plurality of gratings on the optical material by interfering the signal light and the reference light. A miniature microscope is also disclosed.

Light-emitting devices for motor vehicles are provided, which comprise a reflection hologram. A light-guiding body is provided to direct light from a light source arrangement (4) onto the hologram.

A holographic 3D recording device includes: a photorefractive crystal and a microlens array. The microlens array includes an array face and a side face. The microlens array is provided in a light path from an object to be photographed to the photorefractive crystal such that first light of object emitted through a diffuse reflection of the object to be photographed passes through the array face of the microlens array and becomes second light of object that is emitted to the photorefractive crystal. The photorefractive crystal is configured to receive the second light of object emitted by the microlens array and reference light, respectively, and save therein an interference fringe formed by the reference light and the second light of object. The first light of object and the reference light are coherent light.

Imaging apparatus and methods using diffraction-based illumination are disclosed. An example apparatus includes a diffraction grating to redirect light from a light source toward a sample to thereby illuminate the sample. The example apparatus also includes an image sensor to detect a diffraction pattern created by the illuminated sample.

According to an embodiment, a holographic microscope comprises a light source emitting light to an object, a beam splitter reflecting the light emitted from the light source to the object and transmitting object light reflected from the object, a holographic image sensor sensing information, including a holographic image, by receiving the object light and allowing the object light to coherently interfere with reference light, and an image processor obtaining three-dimensional (3D) information about the object based on the information sensed by the holographic image sensor. The holographic image sensor includes a lens focusing the object light to the holographic image sensor, a filter transmitting a predetermined wavelength band of light of the focused object light, a light receiving unit receiving interference light to sense a holographic image, and a reference light source directly emitting the reference light having the predetermined wavelength band to the light receiving unit.