LENS AND PROJECTOR

• Main Author: TANAHASHI DAISUKE
• Format: Patent
• Language: English
• Published: 09.01.2014
• Subjects: OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHYSICS

PROBLEM TO BE SOLVED: To provide a lens capable of effectively shaping a light beam emitted from a high-NA light source with a high divergence angle and to provide a projector provided with the same.SOLUTION: A single lens has different refractive power in a first direction and a second direction that crosses the first direction on a plane orthogonal to an optical axis in order to shape a light beam, having a substantially elliptical cross-sectional shape in a direction orthogonal to the optical axis, emitted from a light source with a divergence angle such that the cross-sectional shape becomes close to a circle. Defining a first direction as a direction having the smallest light beam diversion angle and a second direction as a direction having the largest light beam diversion angle, the surface shape at least of the incident face of the lens on the light source side is aspherical both in the first direction and the second direction, and the surface shape of the exit face opposite the incident face is non circular arc at least in the second direction. When a convex shape of the lens on the light source side along the optical axis is defined as positive and Cvm2 represents local curvature on the exit face of the lens at a position where a marginal light beam of the second direction passes through, Cvm2≥0 is satisfied.