Abstract: Production of a weft defect on a cloth under weaving is detected by at least two weft detection units arranged side-by-side on a loom along the path of travel of inserted wefts for issuing a defect signal which is then subjected to automatic allocation of a corresponding penalty. Penalty-loaded defect signals are sequentially accumulated at a control counter so that the loom is stopped when a count at the control has exceeded a given threshold. When a defect is removed by manual mending on the loom during a dwell, a corresponding gain is automatically subtracted from the count at the control counter during sequential accumulation in order to subdue the count below the threshold and to allow restarting of the loom. Automatic inspection on the loom can be carried out on a level with conventional manual inspection of the loom.

Abstract: A projector lens comprises, in succession from the screen side, a first lens of positive refractive power, a second lens of positive refractive power having a biconvex shape, a third lens of negative refractive power in a shape of a meniscus with its highly concave surface facing to the screen side and a fourth lens of negative refractive power having a highly concave surface facing to the screen side.

Abstract: Disclosed is a horizontal position detecting device for maintaining the surface of a body to be inspected vertically to the optical axis of a main objective lens. The device includes an illumination optical system and a condenser lens system. The illumination optical system supplies parallel light rays to the surface of the body from the direction oblique to the optical axis of the objective lens. The condenser lens system condenses the light rays supplied by the illumination optical system and reflected by the surface of the body. The optical axes of the illumination optical system and the condenser lens system are arranged substantially symmetrically with respect to the axis of the objective lens.

Abstract: A projection type exposure apparatus has a projection objective lens, a projection negative having a predetermined shape pattern and an alignment mark, and a photosensitive plate having an alignment mark. The shape pattern of the projection negative is projected upon the photosensitive plate by the projection objective lens. Main illuminating optical means illuminates the projection negative with a first wavelength light to which the photosensitive plate is sensitive, and alignment optical means illuminates the projection negative with a second wavelength light to which the photosensitive plate is insensitive. The positional relation between the projection negative and the photosensitive plate is detected using the second wavelength light through the projection objective lens.

Abstract: Disclosed is an illumination optical arrangement including light source means for supplying a substantially collimated light beam, and optical means for shifting the collimated light beam from the light source means toward the central axis of the light beam. The optical means includes an entrance surface axis-symmetrically disposed with a predetermined inclination with respect to the central axis to cause the collimated light beam to be refracted toward the central axis substantially at the same angle, and an exit surface axis-symmetrically disposed with said predetermined inclination with respect to the central axis to cause the light beam from the entrance surface to be refracted in a direction parallel to the central axis.

Abstract: This invention provides an erect type zoom telescopic optical system for a binocular or monocular telescope which consists of a positive lens group nearest to an object, a variator group, a compensator group, an image erect prism positioned between the variator and compensator groups, a field stop positioned at a predetermined definite position where the image of the object is formed by said compensator group movable along the optical axis interlocking with the variator group, and an eye-piece for observing the image of the object formed at the field stop. This invention provides a compact size system with high quality compensating aberrations.