Optical scanning unit with rotatable hologram disc

An optical scanning unit, comprising:

• a light source to emit a beam;
• a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract the beam emitted from the light source;
• a reflecting member to reflect the beam emitted from the light source and diffracted by one of the plurality of holograms into another one of the plurality of holograms;
• a scanning object;
• and
• a fixed hologram to correct the beam diffracted by the rotatable hologram disc and to focus the corrected beam on the scanning object,
• wherein the one hologram corresponds to an inner hologram and the other one hologram corresponds to an outer hologram, with the inner and outer holograms being sequentially formed along a radial direction from a center of the rotatable hologram disc, and
• wherein the inner hologram is of a transmittance type that transmits and diffracts the beam emitted from the light source and the outer hologram is of a reflecting type that reflects and diffracts the beam from the reflecting member reflecting the beam diffracted by the inner hologram.

An optical scanning method for scanning a beam of light across an object, comprising:

• emitting a light beam at a first transmittance type hologram on a rotatable hologram disc;
• diffracting the emitted light beam using the first holy ram;
• on the rotatable hologram disc being concentrically formed along a radial direction of the first hologram;
• diffracting the transmitted light beam using the second hologram;
• and
• transmitting the second hologram diffracted light beam to the object.

An optical scanning method for scanning a beam of light across an object, comprising:

• emitting a light beam at a first hologram on a rotatable hologram disc;
• diffracting the emitted light beam using the first hologram;
• transmitting the first hologram diffracted light beam to a second hologram on the rotatable hologram disc being concentrically formed along a radial direction of the first hologram;
• diffracting the transmitted light beam using the second hologram;
• and
• transmitting the second hologram diffracted light beam to the object,
• wherein the transmitting of the second hologram diffracted light beam includes a reflecting operation performed on the second hologram diffracted light beam by a reflecting member formed on a surface of the rotatable hologram disc that is opposite to another surface of the rotatable hologram disc where the second hologram is formed.

An optical scanning unit, comprising:

• a light source to transmit a light beam on a hologram disc;
• the hologram disc including first and second holograms sequentially formed along a radial direction from a center of the hologram disc;
• and
• a reflecting member, separate from the hologram disc, to reflect a light beam exiting the first hologram to the second hologram.

A hologram disc, comprising:

• a first hologram to generate a first predetermined scan angle;
• and
• a second hologram, sequentially formed after the first hologram along a radial direction from a center of the hologram disc, with the second hologram having a second predetermined scan angle such that a scan angle generated by a diffraction performed by the first and second holograms is greater than either of the first or second predetermined scan angles,
• wherein the first hologram is of a reflecting type and the second hologram is of a transmittance type.

A hologram disc, comprising:

• a first hologram to generate a first predetermined scan angle;
• and
• a second hologram, sequentially formed after the first hologram along a radial direction from a center of the hologram disc, with the second hologram having a second predetermined scan angle such that a scan angle generated by a diffraction performed by the first and second holograms is greater than either of the first or second predetermined scan angles,
• wherein the first hologram is of a transmittance type and the second hologram is of a reflecting type.

A hologram disc, comprising:

• a first hologram to generate a first predetermined scan angle;
• and
• a second hologram, sequentially formed after the first hologram along a radial direction from a center of the hologram disc, with the second hologram having a second predetermined scan angle such that a scan angle generated by a diffraction performed by the first and second holograms is greater than either of the first or second predetermined scan angles,
• wherein the first and second holograms are both of a reflecting type.

An optical scanning unit, comprising:

• light source to emit a beam;
• a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract the beam emitted from the light source;
• a reflecting member to reflect the beam emitted from the light source and diffracted by a reflective type one of the plurality of holograms into another transmittance type one of the plurality of holograms;
• a scanning object;
• and
• a fixed hologram to correct the beam diffracted by the rotatable hologram disc and to focus the corrected beam on the scanning object.

An optical scanning method for scanning a beam of light across an object, comprising:

• emitting a light beam at a first reflective type hologram on a rotatable hologram disc;
• diffracting the emitted light beam using the first hologram;
• transmitting the first hologram diffracted light beam to a second transmittance type hologram on the rotatable hologram disc being concentrically formed along a radial direction of the first hologram;
• diffracting the transmitted light beam using the second hologram;
• and
• transmitting the second hologram diffracted light beam to the object.

An optical scanning method for scanning a beam of light across an object, comprising:

• emitting a light beam at a first reflective type hologram on a rotatable hologram disc;
• diffracting the emitted light beam using the first hologram;
• transmitting the first hologram diffracted light beam to a second reflective type hologram on the rotatable hologram disc being concentrically formed along a radial direction of the first hologram;
• diffracting the transmitted light beam using the second hologram;
• and
• transmitting the second hologram diffracted light beam to the object.

An optical scanning unit, comprising:

• a light source to emit a beam;
• a rotatable hologram disc provided with a plurality of holograms, the holograms being formed concentrically along a radial direction to diffract the beam emitted from the light source;
• a reflecting member, separate from the hologram disc, to reflect the beam emitted from the light source and diffracted by one of the plurality of holograms into another one of the plurality of holograms;
• a scanning object;
• and
• a fixed hologram to correct the beam diffracted by the rotatable hologram disc and to focus the corrected beam on the scanning object.

An optical scanning method for scanning a beam of light across an object, comprising:

• emitting a light beam at a first hologram on a rotatable hologram disc;
• diffracting the emitted light beam using the first hologram;
• reflecting the first hologram diffracted light beam, using a reflector separate from the rotatable hologram disc, to a second hologram on the rotatable hologram disc being concentrically formed along a radial direction of the first hologram;
• diffracting the transmitted light beam using the second hologram;
• and
• transmitting the second hologram diffracted light beam to the object.