PURPOSE: To provide the light transmission body which is capable of emitting highly directive light with high efficiency without depending on the incident angle of incident light, the light source device with which the highly directive light is obtainable with high efficiency by using this light transmission body without depending on the exit characteristics of a light source lamp and is formable to a smaller size and the liquid crystal display device which is formed by using this light source device and has high luminance and high visual field angle.
CONSTITUTION: An approximate spot light source 20 is included in a reflection box 22, of which the inside walls are covered with silver reflection surfaces. A pinhole-like aperture 24 is opened at the front surface of this reflection box 22 and the light transmission body 10 is installed in the pinhole-like aperture 24. The light transmission body 10 is a transparent body of a circular columnar shape and the diameter of its incident end face 12 is 1mm. The diameter of its exit end face 14 is 6.2mm and the length 100mm. The light source light from the approximate spot light source 20 is made incident on the incident end face 12 of the light transmission body 10 from the pinhole-like aperture 24 and repeats total reflection within the light transmission body 10. This light is emitted as the directive light having the high directivity of about ≤10° from the exit end face 14.
FUKUHARA MOTOHIKO
YAMADA FUMIAKI
