Abstract: A surface light source apparatus includes an end face for taking in light emitted from a light source and a main surface for emitting the light. The surface light source apparatus further includes a plurality of structure bodies formed on an opposed surface disposed opposite to the main surface in the surface light source apparatus, each of which has a reflecting surface facing the point light source. Each structure body has a cut-off portion which removes a portion on the reflecting surface in a longitudinal direction of the structure body and in a height direction.

Abstract: A surface light source apparatus includes an end face for taking in light emitted from a light source and a main surface for emitting the light. The surface light source apparatus further includes a plurality of structure bodies formed on an opposed surface disposed opposite to the main surface in the surface light source apparatus, each of which has a reflecting surface facing the point light source. Each structure body has a cut-off portion which removes a portion on the reflecting surface in a longitudinal direction of the structure body and in a height direction.

Abstract: A single focal length lens system comprising: at least a front lens unit having positive or negative power, and being fixed in focusing; a focusing lens unit having positive power, and moving along an optical axis in focusing; and a rear lens unit having negative power, and being fixed in focusing, wherein the focusing lens unit includes: a cemented lens of a negative lens and a positive lens; and a positive single lens located on the image side relative to the cemented lens and having an aspheric surface, the rear lens unit is composed of one single lens, and the condition: ?0.5<fW/fGR<?0.1 (fW, fGR: focal lengths of the entire single focal length lens system, the rear lens unit) is satisfied.

Abstract: A single focal length lens system comprising a front lens unit, an aperture diaphragm, and a rear lens unit, wherein the front lens unit is composed of three or less lenses including a negative lens located closest to the object side and a positive lens located on the image side relative to the negative lens, and does not move along an axis in focusing, the rear lens unit includes a focusing lens unit moving along the axis and a fixed lens unit not moving along the axis in focusing, and the conditions: 0.4<fW/fGF<1.5, 0.9<fW/T1<4.5, and ?0.3<fW/fG1<0.3 (fW, fGF, fG1: focal lengths of the entire single focal length lens system, the focusing lens unit, the front lens unit, T1: an axial distance from an object side lens surface of the negative lens to the aperture diaphragm) are satisfied.

Abstract: Provided is a zoom lens system including a compact focusing lens unit and having a suppressed change in image magnification at the time of movement of the focusing lens unit. The zoom lens system of the present invention includes, in order from an object side to an image side, a first lens unit G1 having negative optical power, a second lens unit G2 having positive optical power, a third lens unit G3 having positive optical power, and a fourth lens unit G4 having negative optical power. The fourth lens unit G4 moves to the image side along an optical axis at the time of focusing from an infinity in-focus condition to a close-point in-focus condition.

Abstract: Provided is a zoom lens system including a compact focusing lens unit and having a suppressed change in image magnification at the time of movement of the focusing lens unit. A zoom lens system of the present invention, in order from an object side to an image side, includes, a first lens unit G1 having negative optical power, a second lens unit G2 having positive optical power, a third lens unit G3 having positive optical power, and a fourth lens G4. Condition (10): 1.4<DL/YM<2.5 and condition (11): 1.2<BFW/YM<1.6 are satisfied (where, 100<2?W<140, DL is an effective diameter of the lens surface closest to the image side, BFW is the back focus at a wide-angle limit, YM is the maximum image height at a wide-angle limit, and ?W is a half view angle (°) at a wide-angle limit).

Abstract: A zoom lens system includes a compact focusing lens unit and has a suppressed change in image magnification at the time of movement of the focusing lens unit. The system includes an aperture diaphragm, a first lens unit having negative optical power and being closest to the object side, a third lens unit arranged on the object side relative to the aperture diaphragm and being adjacent to the diaphragm, and a fourth lens unit arranged on the image side relative to the aperture diaphragm and being adjacent to the diaphragm. At the time of zooming, interval between the aperture diaphragm and the third lens unit arranged on the object side relative to the diaphragm and being adjacent to the diaphragm varies, and interval between the aperture diaphragm and the fourth lens unit arranged on the image side relative to the diaphragm and being adjacent to the diaphragm varies.

Abstract: Provided is a zoom lens system including a compact focusing lens unit and having a suppressed change in image magnification at the time of movement of the focusing lens unit. The zoom lens system of the present invention includes, in order from an object side to an image side, a first lens unit G1 having negative optical power, a second lens unit G2 having positive optical power, a third lens unit G3 having positive optical power, and a fourth lens unit G4 having negative optical power. The fourth lens unit G4 moves to the image side along an optical axis at the time of focusing from an infinity in-focus condition to a close-point in-focus condition.

Abstract: Provided is a zoom lens system including a compact focusing lens unit and having a suppressed change in image magnification at the time of movement of the focusing lens unit. The zoom lens system of the present invention includes an aperture diaphragm A, a first lens unit G1 having negative optical power and being closest to the object side, a third lens unit G3 arranged on the object side relative to the aperture diaphragm A and being adjacent to the aperture diaphragm A, and a fourth lens unit G4 arranged on the image side relative to the aperture diaphragm A and being adjacent to the aperture diaphragm A. At the time of zooming, interval between the aperture diaphragm A and the third lens unit G3 arranged on the object side relative to the aperture diaphragm A and being adjacent to the aperture diaphragm A varies, and interval between the aperture diaphragm A and the fourth lens unit G4 arranged on the image side relative to the aperture diaphragm A and being adjacent to the aperture diaphragm A varies.

Abstract: Provided is a zoom lens system including a compact focusing lens unit and having a suppressed change in image magnification at the time of movement of the focusing lens unit. A zoom lens system of the present invention, in order from an object side to an image side, includes, a first lens unit G1 having negative optical power, a second lens unit G2 having positive optical power, a third lens unit G3 having positive optical power, and a fourth lens G4. Condition (10): 1.4<DL/YM<2.5 and condition (11): 1.2<BFW/YM<1.6 are satisfied (where, 100<2?W<140, DL is an effective diameter of the lens surface closest to the image side, BFW is the back focus at a wide-angle limit, YM is the maximum image height at a wide-angle limit, and ?W is a half view angle (°) at a wide-angle limit).