| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical system which uses an LED and achieves a sufficient radiance for the use of a high radiance. <P>SOLUTION: A light-emitting device includes a light-emitting diode (LED), a condenser element such as a composite parabolic condenser, and a wavelength conversion material such as a phosphor. The condenser element receives light from the LED and emits the light from an exit area smaller than an entrance area. The wavelength conversion material is disposed, for example, so as to cover the exit area. The radiance of the LED is kept or increased regardless of the isotropic reemitted light of the wavelength conversion material. In one embodiment, polarization from a polarized LED is supplied to a polarization optical system such as a microdisplay. In another embodiment, orthogonal polarizations from two polarized LEDs are coupled, for example, through a polarizing beam splitter and supplied to a non-polarization optical system such as a microdisplay. Further, the condenser element can be disposed between the beam splitter and the microdisplay. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
