Patent ID: 7476015

Claim:
A backlight apparatus comprising: a light guiding plate which guides light introduced from a light incident side by utilizing total reflection on a light emitting surface as one principal surface and a light reflecting surface as another principal surface and emits light from the light emitting surface based on said surface emitting; and a plurality of white light emission units for emitting white light incident on the light guiding plate, wherein, each white light emission unit includes: a light source group of a first light emitting diode to emit first primary color light, a second light emitting diode to emit second primary color light, a third light emitting diode to emit third primary color light which are arranged in a row, and a color mixing unit for generating white light by mixing the first primary color light emitted from the first light emitting diode, the second primary color light emitted from the second light emitting diode, and the third primary color light emitted from the third light emitting diode, on the light incident side of the light guiding plate, the first light emitting diode, the second light emitting diode, and the third light emitting diode are aligned in a direction perpendicular to one of the principal surfaces of the light guiding plate, and the color mixing unit included in the white light emission unit comprises a first reflecting plate having a light reflecting surface to reflect the first primary color light emitted through a first lens, a first beam splitter plate having a first wavelength-selective transmitting and reflecting surface which transmits the first primary color light reflected on a light reflecting surface of the first reflecting plate and reflects the second primary color light emitted through a second lens, a second reflecting plate adjacent to one end of the first reflecting plate and to one end of the first beam splitter plate and having a light reflecting plate to reflect a diffused portion of the first primary color light to the first beam splitter plate, and a second beam splitter plate having a second wavelength-selective transmitting and reflecting surface to reflect the first primary color light and the second primary color light emitted through the first beam splitter plate and to transmit the third primary color light emitted through a third lens, and generating white light by mixing the first primary color light, the second primary color light, and the third primary color light.