Abstract: The object of the present invention is to further improve a lens barrel moving mechanism of a liquid crystal projector and to provide a lens moving mechanism which has simple structure and is capable of achieving the smooth and high precision movement of a lens barrel, and a liquid crystal projector employing the lens moving mechanism. The present invention provides a lens moving mechanism for moving a lens retaining member 20, which retains a lens barrel 15 provided therein with a projection lens for projecting light with image information, in the directions of Z axis and X axis. The lens moving mechanism comprises first and second guiding mechanisms 23, 23, 24, 24 including a track member, a movable member, and a plurality of rolling members arranged between a rolling member running surface of the track member and a rolling member running surface of the movable member, whereby the lens barrel 15 is guided by the first and the second guiding mechanisms 23, 23, 24, 24 in the directions of Z axis and X axis.

Abstract: The internal focusing telephoto lens includes a first lens group I of positive refractive power, a second lens group II of negative refractive power and a third lens group III of positive refractive power, arranged in order from an object side. The second lens group II is movable along an optical axis for focusing. The first lens group I includes a first positive lens I-1, a second positive meniscus lens I-2 whose object side surface is convex, a third positive meniscus lens I-3 whose object side surface is convex and a fourth negative meniscus lens I-4 whose object side surface is convex, in order from the object side. At least two of the first positive lens I-1, the second positive meniscus lens I-2 and the third positive meniscus lens I-3 in the first lens group I satisfy the following conditions (1) and (2); 1.55<nI<1.75  (1) 61<&ngr;I  (2) where nI is refractive index and &ngr;I is Abbe number of the lenses in the first lens group I.

Abstract: A color image readout lens usable within a magnification range from −0.6X to −1.7X comprises, successively from the object side, a first lens group G1 comprising by a lens having a positive refracting power with a convex surface directed onto the object side, a second lens group G2, comprising by a cemented lens, composed of a biconvex lens and a biconcave lens, having a negative refracting power as a whole with a convex surface directed onto the object side, a third lens group G3, comprising a cemented lens, composed of a biconcave lens and a biconvex lens, having a negative refracting power as a whole with a convex surface directed onto an image side, a fourth lens group G4 comprising a positive lens with a convex surface directed onto the image side, and a fifth lens group G5 comprising a negative meniscus lens with a stronger concave surface directed onto the object side. The color image readout lens further satisfies predetermined conditional expressions.

Abstract: An eyepiece system comprising, in order from the object side, a first lens unit having a negative refractive power and a second lens unit having a positive refractive power, and configured to locate an intermediate image formed by an objective lens system between the first lens unit and the second lens unit: the first lens unit being a negative lens unit having an object side surface which is convex toward the object side. This eyepiece system has a wide visual field and a long eye relief, and corrects aberrations favorably even at marginal portions of the visual field.