Fujitsu Corporation

Shigeo Kayashima

Shinya Hasegawa

Satoshi Maeda

Hirokazu Aritake

Fumio Yamagishi

Shigetake Iwata

Masato Nakashima

Mamoru Hokari

Manabu Ishimoto

Yoshihiro Mizuno

Shin Eguchi

Takahiro Matsuda

Hiroyasu Yoshikawa

Youji Houki

An optical deflection apparatus includes a pair of transparent electrodes, a liquid crystal layer, put between the transparent electrodes, in which stripes are formed at intervals based on a waveform of a driving signal supplied to the pair of transparent electrodes, the stripes functioning as a grating by which incident light is deflected in a deflecting direction, and a driving unit for supplying to the pair of transparent electrodes the driving signal having a waveform by which the deflecting direction changes with time.

Optical deflection apparatus in which deflection angle is continuously

A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems such as optical lenses or a mirror having curvature, and capable of compensating for disadvantages including scanning beam thickening and variation, failure of a rotatable hologram to rotate at a constant velocity, displacement of a scanning beam position in the scanning direction and the cross scanning direction due to a mode hop of a wavelength of a semiconductor laser, and deviation of a base of rotatable hologram from a parallel state. These disadvantages are detrimental to efforts for increasing the resolution of a hologram scanner and lowering the cost thereof. The light beam scanning apparatus includes at least two holograms with one being fixed and the other rotatable, where a rate of variation of a direction cosine of an object wave recorded on the fixed plate and taken in a scanning direction of the light on the scanning surface is configured to be different from a rate of variation of a direction cosine of the object wave recorded on the fixed plate and taken in a cross scanning direction of the light on the scanning surface, and focal distances of a light incident on said rotatable hologram are configured to be different in the scanning direction and in the cross scanning direction.

Light beam scanning apparatus

A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems such as optical lenses or a mirror having curvature, and capable of compensating for disadvantages including scanning beam thickening and variation, failure of a rotatable hologram to rotate at a constant velocity, displacement of a scanning beam position in the scanning direction and the cross scanning direction due to a mode hop of a wavelength of a semiconductor laser, and deviation of a base of rotatable hologram from a parallel state. These disadvantages are detrimental to efforts for increasing the resolution of a hologram scanner and lowering the cost thereof. The light beam scanning apparatus includes at least two holograms, one rotatable and one fixed, wherein the fixed hologram plate has a phase distribution .PHI..sub.H represented as a difference obtained when subtracting a reference wave phase .PHI..sub.0 from an object wave phase .PHI..sub.R, where X is a scanning direction and Y is a cross scanning direction, C.sub.0, C.sub.1, C.sub.2, Y.sub.0, and Z.sub.0 are constants, where .lambda..sub.2 is a wavelength of said incident light; and .lambda..sub.1 is a wavelength of a constructing wave used for forming said fixed hologram plate.

A high-resolution light-beam scanning apparatus utilizing only mass-producable holograms instead of utilizing auxiliary optical systems such as optical lenses or a mirror having curvature. The light beam scanning apparatus is capable of compensating for disadvantages including scanning beam thickening and variation, failure of a rotatable hologram to rotate at a constant velocity, displacement of a scanning beam position in the scanning direction and the cross scanning direction due to a mode hop of a wavelength of a semiconductor laser, and deviation of a base of a rotatable hologram from a parallel state, which disadvantages are detrimental to efforts for increasing the resolution of a hologram scanner and lowering the cost thereof. The light beam scanning apparatus incudes at least two holograms with an optical path length difference .DELTA..PHI.&lt;(.lambda..sup.2 /D.lambda.) where &lt; is a constant less than 0.5. The path length is related per the above equation to a wavelength, .lambda., at the center of the light surface, and a wavelength displacement .DELTA..lambda. measured from the wavelength .check mark. at the center of the light surface.

A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems such as an optical lens or a mirror having curvature, and capable of compensating for disadvantages including scanning beam thickening and variation, failure of a rotatable hologram to rotate at a constant velocity, displacement of a scanning beam position in the scanning direction and the cross scanning direction due to a mode hop of a wavelength of a semiconductor laser, and deviation of a base of a rotatable hologram from a parallel state, which disadvantages are detrimental to efforts for increasing the resolution of a hologram scanner and lowering the cost thereof, the light-beam scanning apparatus being characterized in that provided in the rotatable hologram (1) and the fixed plate (2) are diffraction gratings for minimizing: either a sum total of values obtained by weighting: a square of an optical path length difference between a) an optical path of a light flux measured along a principal axis MA of a light beam incident on and diffracted by a diffraction grating (1a) of a rotatable hologram (1), and incident on and diffracted by a diffraction grating (2a) of a fixed plate (2) so as to conduct a scanning and converging on a scanning point k on an image formation surface (4), and b) an optical path of a light flux measured along a marginal ray M1 distanced from the principal axis MA; or an absolute value of the optical path difference thereof, the weighting being conducted at every scanning position covering an entire range of the image formation surface (4), 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 k on the image formation surface (4), which displacement is measured along the marginal ray M1 distanced from the principal axis MA of an incident reconstructing light flux with respect to the principal axis MA of a phase of the diffraction grating (1a) of the rotatable hologram (1); to an amount of displacement of the same light, which displacement is measured with respect to the principal axis MA of a phase recorded on the diffraction grating (2a) when the light flux is incident on the fixed plate (2); or by weighting an absolute value of the sum, the weighting being conducted at every scanning position covering an entire range of an image formation surface.

Light beam scanning apparatus using a rotating hologram and a fixed

A method of manufacturing a fixed hologram plate of a light-beam scanning apparatus for diffracting a light incident from a light source portion by a rotatable hologram, scanning by the diffracted light through the rotation of the rotatable hologram, diffracting the resulting light by the fixed hologram plate, and for conducting a light-beam scanning on a scanning surface. The method includes the steps of preparing an interference fringe distribution of the fixed hologram plate by two waves: a first wave having a spherical aberration, a transverse aberration of the first wave is in the Y direction, the transverse wave including an astigmatism and a coma; and a second wave having a spherical aberration and astigmatism, and having a wavelength different from a wavelength of a reconstructing wave that is selected to minimize distortion, wherein a transverse aberration of the second wave is in the X direction.

Method for manufacturing 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.

A light-beam scanning apparatus including a rotatable hologram and a fixed plate, which are provided with diffraction gratings to minimize: either a sum total of values obtained by weighting where 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 diffraction grating of a rotatable hologram, and incident on and diffracted by a diffraction grating of a fixed plate so as 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. Another sum total obtained by weighting requiring minimization is: 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, 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 diffraction grating of the rotatable hologram 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 over every scanning position of the formation surface.

Light distributing apparatus for dividing the light from a light source

An optical scanning system includes a laser source, a deflector deflecting a laser beam emitted from the laser source, and at least two hologram elements located between the deflector and an image forming member.

Optical scanning system including two hologram elements

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.

Method of manufacturing light beam scanning apparatus and fixed hologram

An optical deflector device includes a VGM cell including a film of a nematic liquid crystal material which generates a distribution of spatial frequencies when subjected to an electric field. A film thickness setting unit sets a thickness distribution of the film in the VGM cell in accordance with a film thickness distribution defined by a predetermined function.

Optical deflector device

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

A laser beam passes through two holograms or through a hologram twice to reduce the ratio .lambda./d so that P-polarized light, as well as S-polarized light, can be diffracted with high diffraction efficiency and uses a hologram or holograms formed on a base plate and facilitates the separation of a stamper from the base plate in producing replicas of the hologram. A laser beam (5) passes through two holograms formed on a transparent base plate or through a hologram formed on a transparent base plate twice. The ratio .lambda./d, where .lambda. is the wavelength of the laser beam and d is the grating constant of the hologram, is in the range of 0.4 to 1.1.

Growing community of inventors

Kawasaki, Japan

Shigeo Kayashima