Side emitting device, backlight unit using the same as light source and liquid crystal display employing the backlight unit

A backlight unit comprising:

• an array of the side emitting devices arranged on a base plate, each side emitting device comprising:
• a light-emitting device to emit light;
• and
• a side emitter to change a path of at least a part of the light incident from the light-emitting device,
• wherein when a main direction of the light emitted from the emitting device is an upward direction, a direction opposite to the upward direction is a downward direction, and an axis perpendicular to the main direction is a horizontal axis, and the side emitter includes:
• a first reflecting surface to reflect the light emitted from the light-emitting device in a first range of angles close to a central axis;
• a first refracting surface to refract the light reflected by the first reflecting surface obliquely downward with respect to the horizontal axis, and
• a second refracting surface to refract the light emitted from the light-emitting device in a second range of angles outside of the first range of angles;
• a reflection diffusion plate disposed under the side emitting devices, to diffuse and reflect the light incident from the side emitting device;
• and
• a first transmission diffusion plate disposed above the side emitting devices, to diffuse and transmit the incident light.

A liquid crystal display comprising:

• a liquid crystal panel;
• and
• the backlight unit to emit light to the liquid crystal panel, the backlight unit comprising:
• an array of the side emitting devices arranged on a base plate, and each side emitting device includes:
• a light-emitting device to emit light, and
• a side emitter to change a path of at least a part of the light incident from the light-emitting device,
• wherein when a main direction of the light emitted from the emitting device is an upward direction, a direction opposite to the upward direction is a downward direction, and an axis perpendicular to the main direction is a horizontal axis, and the side emitter includes a first reflecting surface to reflect the light emitted from the light-emitting device in a first range of angles close to a central axis, a first refracting surface to refract the light reflected by the first reflecting surface obliquely downward with respect to the horizontal axis, and a second refracting surface to refract the light emitted from the light-emitting device in a second range of angles outside of the first range of angles,
• a reflection diffusion plate disposed under the side emitting devices, to diffuse and reflect the light incident from the side emitting device, and
• a first transmission diffusion plate disposed over the side emitting device, to diffuse and transmit incident light.

An illumination controlling apparatus comprising:

• a base portion that contacts a light-emitting device to receive the emitted light therefrom;
• a first cone-shaped reflecting surface to reflect the light received within a first range of angles with respect to a central axis thereof;
• a first refracting surface to refract the light reflected by the first reflecting surface obliquely and back toward the light emitting device;
• and
• a second refracting surface to refract the light received within a second range of angles complementary to the first range of angles with respect to a central axis thereof.

A method of redirecting light emitted by a Lambertian light source mounted on a base surface, wherein when a central axis is perpendicular to the base surface passing through the Lambertian light source, and an axis perpendicular to the central axis passing through the Lambertian light source is a horizontal axis, the method comprising:

• changing a path of at least a part of the light from the Lambertian light source emitted in a first range of angles close to the central axis;
• refracting the light with changed path obliquely with respect to the horizontal axis towards the Lambertian light source;
• and
• refracting a first portion of the light from the Lambertian light source emitted in a second range of angles complementary to the first range of angles obliquely with respect to the horizontal axis towards the Lambertian light source.