A liquid crystal display (LCD) panel with a backlight module including a light-emitting diode (LED)-based illumination device is disclosed. The illumination device includes more than one LED of the waveguide type for use as a light source of the backlight. The LCD panel includes a pair of substrates, a liquid crystal (LC) layer interposed between these substrates, and a polarization plate. Output light of the LED is linearly polarized in advance. A waveguide is arranged for giving off polarized light components from the LED only in a chosen direction to thereby permit incidence in parallel with a polarized light transmission direction of the LCD polarizer plate. The LED is amounted and arranged so that the polarized light transmission direction of the polarizer plate is the same as the polarization direction through an optical system associated therewith.