Fujitsu Corporation

Shigetake Iwata

Shinya Hasegawa

Satoshi Maeda

Fumio Yamagishi

Shigeo Kayashima

Hirokazu Aritake

Masato Nakashima

Mamoru Hokari

Hiroyuki Ikeda

Youji Houki

Shin-ya Hasegawa

A holographic recording apparatus includes first and second light sources for respectively generating first and second light beams. A mask is located in front of a hologram recording material and has an aperture. Interference fringes are recorded in a hologram cell on the hologram recording material corresponding to the aperture. A movement mechanism supports the hologram recording material masked by the mask and relatively moves the hologram recording material with respect to the mask in predetermined directions so that an interference pattern is formed in an area on the hologram recording material. A spatial frequency changing mechanism changes incident angles of the first and second light beams with respect to the mask.

Holographic recording apparatus and holographic optical element

A high-resolution light-beam scanning apparatus including a rotatable hologram and a fixed plate which are diffraction gratings for minimizing either a sum total of values obtained by weighting (1): a square of an optical path length difference between a) an optical path of a light flux measured along a principal axis of a light beam incident on and diffracted by a first diffraction grating of the rotatable hologram, and incident on and diffracted by a second diffraction grating of the fixed plate so as to conduct a scanning and converging on an image formation surface scanning point, and b) an optical path of a light flux measured along a marginal ray distanced from the principal axis, or an absolute value of the optical path difference thereof; or (2) a square of a sum obtained by adding an amount of displacement of a light beam convergent on the scanning point, which displacement is measured along the marginal ray distanced from the principal axis of an incident reconstructing light flux with respect to the principal axis of a phase of the first diffraction grating, to an amount of displacement of the same light, which displacement is measured with respect to the principal axis of a phase recorded on the second diffraction grating, when the light flux is incident on the fixed plate, or by weighting an absolute value of the sum, each weighting being conducted at every scanning position covering an entire range of the image formation surface.

Light beam scanning apparatus

A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems, and capable of compensating for disadvantages. The light-beam scanning apparatus including diffraction gratings for minimizing either: a sum total of values obtained by weighting a square of an optical path length difference between an optical path of a light flux measured along a principal axis of a light beam incident on and diffracted by a first diffraction grating of a rotatable hologram, and incident on and diffracted by a second diffraction grating of a fixed plate to conduct a scanning and converging on a scanning point on an image formation surface, and an optical path of a light flux measured along a marginal ray distanced from the principal axis or an absolute value of the optical path difference thereof; or a sum total of values obtained by weighting a square of a sum obtained by adding an amount of displacement of a light-beam convergent on a scanning point on the image formation surface, to an amount of displacement of the same light. The displacement measured with respect to the principal axis of a phase recorded on the diffraction grating when the light flux is incident on the fixed plate or by weighting an absolute value of the sum. The weighting is conducted at every scanning position of an image formation surface.

Method of manufacturing light beam scanning apparatus and fixed hologram

A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems, and capable of compensating for disadvantages. The light-beam scanning apparatus including diffraction gratings for minimizing either: a sum total of values obtained by weighting a square of an optical path length difference between an optical path of a light flux measured along a principle axis of a light beam incident on and diffracted by a first diffraction grating of a rotatable hologram, and incident on and diffracted by a second diffraction grating of a fixed plate to conduct a scanning and converging on a scanning point on an image formation surface, and an optical path of a light flux measured along a marginal ray distanced from the principal axis or an absolute value of the optical path difference thereof; or a sum total of values obtained by weighting a square of a sum obtained by adding an amount of displacement of a light-beam convergent on a scanning point on the image formation surface, to an amount of displacement of the same light. The displacement measured with respect to the principal axis of a phase recorded on the diffraction grating when the light flux is incident on the fixed plate or by weighting an absolute value of the sum. The weighting is conducted at every scanning position of an image formation surface.

Light beam scanning apparatus comprising a first and second diffraction

An optical beam scanning apparatus includes one rotatable hologram which is rotatable about an axis, and at least two laser beam sources which emit laser beams. The rotatable hologram is provided with at least two hologram areas whose number corresponds to the number of the laser beam sources, so that the laser beams emitted from the respective laser beam sources are made incident upon the respective hologram areas. Each of the hologram areas is provided with a plurality of hologram facets which are concentrically arranged with respect to the axis of rotation of the rotatable hologram to emit laser beams of the same F number. The hologram areas having different numbers of hologram facets having different F numbers.

Optical beam scanning apparatus

A light beam scanning apparatus includes a rotatable holographic disk having a hologram which is constructed by an interference of a reference wave and an objective wave, which is a coma wave, the coma wave having a focal length which decreases toward the outer periphery from the inner periphery of the holographic disk in a radial direction. The focal length has a different direction perpendicular to the radial direction, so that when the hologram of the holographic disk which rotates is reconstructed by a reconstruction wave, the scanning is effected by the beams diffracted by the hologram.

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Kawasaki, Japan

Shigetake Iwata