Beam deflector, 3-dimensional display device including the same, and method of deflecting beam

A method of deflecting a beam, the method comprising:

• deflecting, by a first deflection element, light of a first wavelength band having a first polarization direction in a first direction;
• changing, by a first general-purpose polarization conversion element, a polarization direction of the light of the first wavelength band from the first polarization direction to a second polarization direction that intersects the first polarization direction, and converting a polarization direction of light of a second wavelength band that is different from the first wavelength band from the second polarization direction to the first polarization direction;
• deflecting, by a second deflection element, the light of the first wavelength band having the second polarization direction in a second direction that intersects the first direction;
• deflecting, by a third deflection element, the light of the second wavelength band having the first polarization direction in the first direction;
• converting, by a second general-purpose polarization conversion element, a polarization direction of the light of the second wavelength band from the first polarization direction to the second polarization direction, and converting the polarization direction of the light of the second wavelength band from the second polarization direction to the first polarization direction;
• deflecting, by a fourth deflection element, the light of the second wavelength band having the second polarization direction in the second direction;
• deflecting, by a fifth deflection element, the light having the first polarization direction in the second direction;
• converting, by a third general-purpose polarization conversion element, the polarization direction of the light of the first wavelength band, the polarization direction of the light of the second wavelength band, and the polarization direction of the light of the third wavelength band;
• deflecting, by a sixth deflection element, the light having the second polarization direction in the first direction;
• and
• changing, by a final polarization conversion element, the polarization direction of the light of the first wavelength band, the polarization direction of the light of the second wavelength band, and the polarization direction of the light of the third wavelength band to coincide with one another,
• wherein the light of the first wavelength band and the light of the second wavelength band sequentially pass through the first deflection element, the first general-purpose polarization conversion element, the second deflection element, the third deflection element, the second general-purpose polarization conversion element, and the fourth deflection element.

A three-dimensional (3D) display device comprising:

• a light source configured to emit a light beam comprising a plurality of wavelength bands;
• a beam deflector configured to deflect the light beam;
• at least one processor configured to control the beam deflector to deflect light in a predetermined direction;
• and
• a spatial light modulator configured to diffract the light beam to form a holographic image,
• wherein the beam deflector comprises:
• a first sub deflector configured to deflect light of a first wavelength band in a first direction and a second direction that intersects the first direction, and convert a polarization direction of the light of the first wavelength band;
• and
• a second sub deflector configured to deflect light of a second wavelength band that is different from the first wavelength band in the first direction and the second direction, and convert a polarization direction of the light of the second wavelength band;
• a third sub deflector configured to deflect light of a third wavelength band that is different from the first wavelength band and the second wavelength band, respectively;
• and
• a final polarization conversion element configured to change the polarization direction of the light of the first wavelength band, the polarization direction of the light of the second wavelength band, and the polarization direction of the light of the third wavelength band to coincide with one another, and
• wherein the first sub deflector, the second sub deflector, and the third sub deflector are provided in a path of the light beam emitted from the light source.

A beam deflector comprising:

• a first sub deflector configured to deflect light of a first wavelength band in a first direction and a second direction that intersects the first direction, and convert a polarization direction of the light of the first wavelength band;
• a second sub deflector configured to deflect light of a second wavelength band, that is different from the first wavelength band in the first direction and the second direction, and convert a polarization direction of the light of the second wavelength band;
• a third sub deflector configured to deflect light having a third wavelength band that is different from the first wavelength band and the second wavelength band, respectively, and convert the polarization direction of the light of the first wavelength band, the polarization direction of the light of the second wavelength band, and a polarization direction of the light of the third wavelength band;
• and
• a final polarization conversion element configured to change the polarization direction of the light of the first wavelength band, the polarization direction of the light of the second wavelength band, and the polarization direction of the light of the third wavelength band to coincide with one another,
• wherein the first sub deflector, the second sub deflector, and the third sub deflector are sequentially provided such that the light of the first wavelength band, the light of the second wavelength band, and light of the third wavelength band sequentially pass through the first sub deflector, the second sub deflector, and the third sub deflector.