LED lighting device, and method of extracting light using LED lighting device

Method of extracting light using an LED lighting device, the LED lighting device comprising:

• an outer frame made of microcellular foam resin;
• and
• an inner frame arranged inside the outer frame and made of the microcellular foam resin,
• both of the inner frame and the outer frame having openings provided at respective upper portions and recess portions formed downwardly from the openings, respectively,
• the recess portions of the inner frame and the outer frame being spaced apart from and face each other,
• a surface side of the inner frame functioning as a reflector plate, a space surrounded by the surface side of the inner frame and the opening of the inner frame forming a first light guide space, a rear face side of the inner frame and a surface side of the outer frame functioning as reflector plates, respectively, a space surrounded by a rear face side of the inner frame, the surface side of the outer frame, and the openings of the inner frame and the outer frame forming a second light guide space,
• a first LED light source being arranged in the first light guide space and a second LED light source being arranged in the second light guide space,
• the opening of the inner frame serving as a first light extraction portion, an opening formed around the first light extraction portion and surrounded by the openings of the inner frame and the outer frame serving as a second light extraction portion,
• the opening of the inner frame being formed on a substantially same plane,
• the opening of the outer frame and the opening of the inner frame being formed on a same plane, or alternatively the opening of the outer frame being arranged behind the opening of the inner frame, and
• the method comprising:
• extracting, from the first light extraction portion, light in an opening face direction of the opening of the inner frame, and
• extracting, from the second light extraction portion, light in an opening face direction of the opening of the inner frame, or in a direction including either an opening face direction of the opening of the inner frame or a side face direction intersecting therewith at a predetermined angle.