Abstract: An imaging lens which uses a larger number of constituent lenses for higher performance and features a low F-value, low-profile design and a wide field of view. Designed for a solid-state image sensor, the imaging lens includes constituent lenses arranged in order from an object side to an image side: a first positive refractive power lens; a second negative refractive power lens; a third lens; a fourth lens; a fifth lens; a sixth lens having a concave image-side surface near an optical axis; and a seventh negative refractive power lens.

Abstract: An imaging lens which uses a larger number of constituent lenses for higher performance and features a low F-value, low-profile design and a wide field of view. Designed for a solid-state image sensor, the imaging lens includes constituent lenses arranged in order from an object side to an image side: a first positive refractive power lens having a convex object-side surface; a second negative refractive power lens having a concave image-side surface; a third positive refractive power lens having a convex image-side surface; a fourth negative refractive power lens having a concave image-side surface; a fifth positive refractive power lens as a meniscus lens having a convex image-side surface; a sixth lens as a meniscus double-sided aspheric lens having a concave image-side surface near an optical axis; and a seventh negative refractive power lens as a double-sided aspheric lens having a concave image-side surface near the optical axis.

Abstract: A compact low-cost imaging lens which provides brightness with an F-value of 2.5 or less and a wide field of view and corrects aberrations properly, meeting the demand for low-profileness. The imaging lens elements are arranged in order from an object side, an aperture stop, positive first lens having convex object-side and image-side surfaces, negative meniscus second lens having a concave image-side surface, positive third lens having at least one aspheric surface, positive double-sided aspheric fourth lens, and negative double-sided aspheric fifth lens having concave object-side and image-side surfaces with its image-side surface having a pole-change point off the axis. It satisfies conditional expressions below: 0.5<f1/f<1.0??(1) 10.0<f3/f??(2) 0.8<(r3+r4)/(r3?r4)<2.

Abstract: An imaging lens comprising, in order from the object side: an aperture stop; a positive first lens having convex object-side and image-side surfaces; a double-sided aspheric negative second lens having a concave object-side surface; a meniscus double-sided aspheric positive third lens having a convex image-side surface; and a meniscus double-sided aspheric negative fourth lens having a concave image-side surface. All of the lenses are made of a plastic material.

Abstract: An imaging lens includes four lenses arranged in order from the object side to the image side: an aperture stop, positive (refractive power) first lens having a convex object-side surface near the optical axis, second lens having a positive meniscus shape near the axis, positive third lens having a convex image-side surface near the axis, and negative fourth lens having a concave image-side surface near the axis. All lens surfaces are aspheric. The image-side aspheric surface of the fourth lens has a pole-change point off the optical axis and conditional expressions (1) and (2) are satisfied: 0.75<TLA/(2IH)<0.90??(1) 0.90<TLA/f<1.30??(2) where TLA: distance on the optical axis from the first lens's object-side surface to the image sensor's image plane without a filter between the fourth lens and image sensor IH: maximum image height f: overall optical system focal length.

Abstract: An imaging lens includes a first lens; a second lens; and a third lens arranged from an object side to an image plane side. The first lens has an object-side surface with a positive curvature radius. The second lens has an object-side surface and an image plane-side surface with negative curvature radii. The third lens has an object-side surface and an image plane-side surface with positive curvature radii. The object-side surface and the image plane-side surface of the third lens are respectively formed as an aspheric shape having an inflexion point. When the whole lens system has a focal length f, the first lens has a focal length f1, the second lens has a focal length f2, and the third lens has a focal length f3, the imaging lens satisfies the following conditional expressions: f1<f2 1.0<f1/f<1.5 0.7<f2/f3<1.2.

Abstract: An imaging lens which uses a larger number of constituent lenses for higher performance and features a low F-value, low-profile design and a wide field of view. Designed for a solid-state image sensor, the imaging lens includes constituent lenses arranged in order from an object side to an image side: a first positive refractive power lens having a convex object-side surface; a second negative refractive power lens having a concave image-side surface; a third positive refractive power lens having a convex image-side surface; a fourth negative refractive power lens having a concave image-side surface; a fifth positive refractive power lens as a meniscus lens having a convex image-side surface; a sixth lens as a meniscus double-sided aspheric lens having a concave image-side surface near an optical axis; and a seventh negative refractive power lens as a double-sided aspheric lens having a concave image-side surface near the optical axis.

Abstract: A compact high-resolution imaging lens which provides a wide field of view of 80 degrees or more and corrects various aberrations properly. Designed for a solid-state image sensor, the imaging lens includes constituent lenses arranged in the following order from an object side to an image side: a first positive (refractive power) lens having a convex object-side surface; a second negative lens having a concave image-side surface; a third positive lens as a double-sided aspheric lens having a convex object-side surface; a fourth positive lens having a convex image-side surface; a fifth lens as a double-sided aspheric lens having a concave image-side surface; and a sixth negative lens having a concave image-side surface. The image-side surface of the sixth lens has an aspheric shape with a pole-change point in a position off an optical axis.

Abstract: A wide-angle image pickup lens having small F-value, high resolution, and small distortion is provided. The image pickup lens is configured from, in order from an object side to an image side, a first lens having a positive refractive power with a concave surface facing the object side, an aperture stop, a second lens having a negative refractive power with a concave surface facing the image side, a third lens having a positive refractive power, a fourth lens having a positive refractive power with a concave surface facing the object side, and a fifth lens having a negative refractive power with a concave surface facing the image side.

Abstract: Arranged in order from an object side are: an aperture stop; a positive (refractive power) first lens having convex object-side and image-side surfaces; a double-sided aspheric negative second lens having a concave object-side surface; a meniscus double-sided aspheric positive third lens having a convex image-side surface; and a meniscus double-sided aspheric negative fourth lens having a concave image-side surface. All the lenses are made of plastic material and conditional expressions below are satisfied: 0.56<r1/f<1.10??(1) 0.86<f1/f3<1.41??(2) ?5.0<r3/r4<0.1??(3) 2.0<r7/r8<4.

Abstract: An imaging lens includes four lenses arranged in order from the object side to the image side: an aperture stop, positive (refractive power) first lens having a convex object-side surface near the optical axis, second lens having a positive meniscus shape near the axis, positive third lens having a convex image-side surface near the axis, and negative fourth lens having a concave image-side surface near the axis. All lens surfaces are aspheric. The image-side aspheric surface of the fourth lens has a pole-change point off the optical axis and conditional expressions (1) and (2) are satisfied: 0.75<TLA/(2IH)<0.90??(1) 0.90<TLA/f<1.

Abstract: An imaging lens includes, from the object side to the image side, an aperture stop, a first lens with positive refractive power having a convex object-side surface near an optical axis, a second lens with positive refractive power having a convex image-side surface near the axis, a third lens with positive refractive power having a convex image-side surface near the axis, and a fourth lens with negative refractive power having a concave image-side surface near the axis, wherein all lens surfaces are aspheric, all lenses are made of plastic material, a diffractive optical surface is formed on at least one of the lens surfaces from the first lens image-side surface to the second lens image-side surface, and at least one of the three positive lenses satisfies expression (1): 1.58<Ndi??(1) where Ndi: refractive index of the i-th positive lens at d-ray.

Abstract: A laser welded steel pipe having a weld zone containing a steel pipe containing 0.01 to 0.2 weight % C, 1 weight % or less S, 0.05 to 2 weight % Mn and 6 weight % or less Mn. The weld zone has a melted and solidified metal structure containing carbon and oxygen which satisfy the following equations:(carbon weight %)(oxygen weight %).ltoreq.0.006for a steel pipe containing carbon in an amount of less than 0.2 weight %, and(oxygen weight %).gtoreq.0.02.A method for manufacturing a laser-welded steel pipe including producing an open pipe made from a hot-rolled steel strip with opposing edge portions facing each other by employing a formal roll, preheating the two edge portions, pressing the two edge portions to butt against each other by using squeeze rolls and welding the butted edge portions by irradiation with a laser beam to heat and melt the two edge portions.

Abstract: A laser-welded steel pipe includes: a steel pipe consisting essentially of C in an amount of 0.01 to 0.5 wt. %, Si in an amount of 1 wt. % or less, Mn in an amount of 0.05 to 2 wt. % and Cr in an amount of 6 wt. % or less; and a weld zone having a melted and solidified metal structure containing carbon and oxygen. The carbon content, ?C wt. %!, and the oxygen content, ?O wt. %!, in the melted and solidified metal structure satisfies the following equations:?C wt. %!.times.?O wt. %!.ltoreq.0.006, for the steel pipe containing C in an amount of less than 0.2 wt. %,?O wt. %!.ltoreq.0.03, for the steel pipe containing C in an amount of 0.2 wt. % or more.

Abstract: An ECG diagnostic pad having upper fit portions with upper limb lead electrodes, central fit portions with unipolar precordial lead electrodes and lower fit portions with flank lead electrodes is fitted onto the chest wall of a human subject. Only by attaching the pad onto the chest wall of the subject, the lead electrodes can readily be brought in close contact with the desired locations prescribed anatomically on the chest wall with accuracy.

Abstract: In this pencil type heart potential waveform measuring device, a first electrode is provided at the tip of a substantially round bar-like pencil device body, a second electrode is separated from the above mentioned first electrode on the outer periphery of a gripping part of the pencil body, a memorizing device for memorizing heart potential waveforms induced from the first and second electrodes is provided within the pencil body and an output terminal for output of heart potential waveform signals memorized in the memorizing device is provided in the pencil body.

Abstract: A method of and apparatus for manufacturing a pair of paper stringer tapes for slide fasteners from a pair of blank paper strips of a continuous length. The blank paper strips are fed lengthwise through a guide roller assembly. A pair of parallel spaced scoring wheels is biased against one guide roller of the guide roller assembly. As the paper strips pass between the one guide roller and the respective scoring wheels, a pair of continuous prospective folding lines of a constant depth is formed on the blank paper strips along the respective inner longitudinal margin thereof. The inner longitudinal margin of each paper strip is folded on the folding line to provide a doubled thickness with a folded edge on which a row of thermoplastic coupling elements is to be mounted. The support of the scoring wheels enables them to move toward and away from the strip, either jointly or individually, to compensate for variations in paper thickness, whereby said constant depth is maintained.