PROJECTING LENS AND IMAGE DISPLAY DEVICE PROVIDED THEREWITH

PROBLEM TO BE SOLVED: To more enhance high resolution, high luminance and a long focal distance of a projecting lens and to allow the projecting lens to be reduced in size.SOLUTION: A projecting lens 28 provided on an optical path for projecting laser light of green, red and blue is constituted of four lenses of first, second, third and fourth lenses L1, L2, L3 and L4 from a projection side. A diaphragm STO is provided between the first and second lenses L1 and L2. The first and fourth lenses L1 and L4 are constituted of plastic lenses, and the second and third lenses L2 and L3 are constituted of glass lenses. By causing lenses disposed at positions where energy density of light emitted from a laser light source device is high to be constituted of the glass lenses, large light resistance, especially light resistance of the blue laser light, can be secured. In addition, by causing outermost lenses to be constituted of the plastic lenses capable of being freely formed in any shape, high resolution, high luminance and a long focal distance can be realized by a compact projecting lens.