Light source lighting device and projection display apparatus
View Patent ↗A light source lighting device includes: a laser light source unit; a converging lens that converges a plurality of light beams emitted from the laser light source unit; a diffuser plate that diffuses a plurality of light beams converged by the converging lens; and a second collimating lens that collimates a light beam diffused by the diffuser plate. The converging lens has an aspherical surface, the second collimating lens has a spherical surface, the aspherical surface of the converging lens has an aspherical surface coefficient that is set to cancel a positive spherical aberration of the second collimating lens. A luminous flux density in a proximity of an optical axis is lower than a luminous flux density in a peripheral part away from the optical axis, the optical axis being an axis of a light beam emitted from the second collimating lens.
1. A light source lighting device comprising:
a laser light source unit including
a plurality of semiconductor lasers, and
a first collimating lens that collimates a plurality of light beams emitted from the plurality of semiconductor lasers;
a converging lens that converges a plurality of light beams emitted from the laser light source unit;
at least one diffuser plate that diffuses a plurality of light beams converged by the converging lens; and
a second collimating lens that collimates a light beam diffused by the at least one diffuser plate,
wherein the converging lens has an aspherical surface,
the second collimating lens has a spherical surface,
the aspherical surface of the converging lens has an aspherical surface coefficient that is set to cancel a positive spherical aberration of the second collimating lens, and
a luminous flux density in a proximity of an optical axis is set to be lower than a luminous flux density in a peripheral part away from the optical axis, the optical axis being an axis of a light beam emitted from the second collimating lens.
2. The light source lighting device according to claim 1 , wherein
the converging lens has the aspherical surface that serves as an incident surface and a planar surface that serves as an emission surface, and
the second collimating lens has a planar surface that serves as an incident surface and the spherical surface that serves as an emission surface.
3. The light source lighting device according to claim 2 , wherein a conical coefficient K of the incident surface of the converging lens satisfies a relationship −1.3≤K≤−0.5.
4. A projection display apparatus comprising:
the light source lighting device according to claim 1 ;
a light guide that guides emission light from the light source lighting device to an area to be illuminated;
a light modulation element that is disposed in the area to be illuminated and modulates the emission light according to an external signal; and
a projection lens that enlarges and projects the emission light modulated by the light modulation element.