Surface illumination apparatus and liquid crystal display

A surface illumination apparatus comprising:

• a laser light source which emits a substantially parallel laser beam;
• and
• a light guide plate comprising:
• a first main-surface portion;
• a second main-surface portion opposite said first main-surface portion;
• a first end-surface portion;
• and a second end-surface portion located opposite said first end-surface portion,
• wherein:
• a laser beam emitted from the laser light source:
• is incident at an inclination angle to the first main-surface portion such that it enters into said light guide plate and the beam is thereafter incident on the second main-surface portion, in said light guide plate, after the direction of an optical path thereof is changed by the first main-surface portion and the beam is reflected within said light guide plate by said first main-surface portion, and is kept polarized and emitted as a substantially parallel beam from the second main-surface portion out of the light guide plate;
• the thickness between the first main-surface portion and the second main-surface portion is substantially constant;
• the first main-surface portion is formed with a first diffraction grating which has a lattice vector in the direction where the laser beam incident on the first end-surface portion advances;
• the second main-surface portion is formed with a second diffraction grating which further diffracts the beam diffracted by the first diffraction grating and emits this beam as a substantially parallel beam;
• and
• the laser beam incident on the first end-surface portion is emitted as a substantially parallel beam from the second main-surface portion after being diffracted by the first diffraction grating and the second diffraction grating.

A surface illumination apparatus comprising:

• a laser light source which emits a substantially parallel laser beam;
• and
• a light guide plate comprising:
• a first main-surface portion;
• a second main-surface portion opposite said first main-surface portion;
• a first end-surface portion;
• and a second end-surface portion located opposite said first end-surface portion,
• wherein:
• a laser beam emitted from the laser light source:
• is incident at an inclination angle to the first main-surface portion such that it enters into said light guide plate and the beam is thereafter incident on the second main-surface portion, in said light guide plate, after the direction of an optical path thereof is changed by the first main-surface portion and the beam is reflected within said light guide plate by said first main-surface portion, and the beam is kept polarized and emitted as a substantially parallel beam from the second main-surface portion out of the light guide plate;
• the first main-surface portion inclines such that the light guide plate becomes thinner from the first end-surface portion toward the second end-surface portion opposite to the first end-surface portion;
• the first main-surface portion is formed with a diffraction grating which has a lattice vector in the direction where the laser beam incident on the first end-surface portion advances;
• and
• the laser beam incident on the first end-surface portion is emitted as a substantially parallel beam from the second main-surface portion after the direction of the optical path thereof is changed by the diffraction grating.

A surface illumination apparatus comprising:

• a laser light source which emits a substantially parallel laser beam;
• a light guide plate comprising:
• a first main-surface portion;
• a second main-surface portion opposite said first main-surface portion;
• a first end-surface portion;
• and a second end-surface portion located opposite said first end-surface portion,
• wherein:
• a laser beam emitted from the laser light source:
• is incident at an inclination angle to the first main-surface portion such that it enters into said light guide plate and the beam is thereafter incident on the second main-surface portion, in said light guide plate, after the direction of an optical path thereof is changed by the first main-surface portion and the beam is reflected within said light guide plate by said first main-surface portion, and the beam is kept polarized and emitted as a substantially parallel beam from the second main-surface portion out of the light guide plate;
• a first laser-beam scan portion which scans the laser beam on the first end-surface portion, in a first direction which connects the first main-surface portion and the second main-surface portion;
• a second laser-beam scan portion which scans the laser beam scanned by the first laser-beam scan portion in a second direction substantially perpendicular to the first direction;
• an optical conversion member which converts the laser beam scanned by the second laser-beam scan portion into a substantially parallel beam;
• and
• a turning-back member which turns back the substantially parallel beam formed after the conversion by the optical conversion member and guides this substantially parallel beam to the first end-surface portion,
• wherein the laser light source, the first and second laser-beam scan portions, the optical conversion member and the turning-back member are disposed on the first main-surface portion.

A surface illumination apparatus comprising:

• a laser light source which emits a substantially parallel laser beam;
• and
• a light guide plate comprising:
• a first main-surface portion;
• a second main-surface portion opposite said first main-surface portion;
• a first end-surface portion;
• and a second end-surface portion located opposite said first end-surface portion,
• wherein:
• a laser beam emitted from the laser light source:
• is incident at an inclination angle to the first main-surface portion such that it enters into said light guide plate and the beam is thereafter incident on the second main-surface portion, in said light guide plate, after the direction of an optical path thereof is changed by the first main-surface portion and the beam is reflected within said light guide plate by said first main-surface portion, and the beam is kept polarized and emitted as a substantially parallel beam from the second main-surface portion out of the light guide plate;
• an enlargement member which enlarges a laser beam emitted from the laser light source in a first direction which connects the first main-surface portion and the second main-surface portion of the light guide plate and in a second direction substantially perpendicular to the first direction;
• an optical conversion member which converts the laser beam enlarged by the enlargement member into a substantially parallel beam;
• and
• a turning-back member which turns back the substantially parallel beam formed after the conversion by the optical conversion member and guides this substantially parallel beam to the first end-surface portion,
• wherein the laser light source, the enlargement member, the optical conversion member and the turning-back member are disposed on the first main-surface portion.

A liquid crystal display, comprising:

• a liquid-crystal display panel;
• and
• a backlight unit which illuminates the liquid-crystal display panel, wherein:
• the backlight unit is formed by a surface illumination apparatus;
• and
• the surface illumination apparatus and the liquid-crystal display panel are arranged so that the polarization-axis angle of a laser beam emitted from the surface illumination apparatus becomes a predetermined angle with respect to the polarization-axis angle of a polarizing plate disposed on the view side of the liquid-crystal display panel;
• said surface illumination apparatus comprising:
• a laser light source which emits a substantially parallel laser beam;
• and
• a light guide plate comprising:
• a first main-surface portion;
• a second main-surface portion opposite said first main-surface portion;
• a first end-surface portion;
• and a second end-surface portion located opposite said first end-surface portion,
• wherein:
• a laser beam emitted from the laser light source:
• is incident at an inclination angle to the first main-surface portion such that it enters into said light guide plate and the beam is thereafter incident on the second main-surface portion, in said light guide plate, after the direction of an optical path thereof is changed by the first main-surface portion and the beam is reflected within said light guide plate by said first main-surface portion, and the beam is kept polarized and emitted as a substantially parallel beam from the second main-surface portion out of the light guide plate.