Abstract: A collimator optical system for effecting elliptical-to-circular cross section is disclosed which comprises two lenses in a slab form whose refractive index distribution in one plane is such that the refractive index decreases gradually from the center outward in the direction of their thickness. The two lenses are spaced on the optical axis in such a way that the direction of refractive index distribution in one lens crossing the direction of refractive index distribution in the other lens at right angles.

Abstract: An automatic focusing binocular is herein disclosed in which a light, signifying the inability of the automatic focusing system to operate due to the lack of available light contrast, is provided within the user's field of vision as he looks through the binocular. This is accomplished by the use of a focus detection module. When the reflected images from apertures proximate to the objective lens coincide in the module, a focusing signal is produced which terminates the motion of the eyepieces at a point corresponding to the distance of the object from the objective lens. When these coinciding images do not have sufficient light contrast for the module to produce the focus signal, a detection signal is produced which illuminates a warning light. A rod-shaped prism is disposed such that light from the light source condenses at the forward focal point of the eyepiece.

Abstract: A housing for binoculars including split upper and lower housing halves which entirely protects the main body of a binoculars including the left and right optical systems, the focusing mechanism and the eyepiece adjustment mechanism. Ocular and objective lens frames project outwardly from the main body of the upper and lower halves of the housing. The two halves of the housing are joined by rings placed over the objective and ocular frames. Only an eyepiece width adjustment knob and a focusing adjustment knob or switch project from the housing so that a tight seal is provided for all internal components.

Abstract: Binoculars including an automatically focussed optical system in which portions of the two incoming light beams are diverted to an automatic focussing module by two mirrors, one of which is fixed and the other movable. The movable mirror is adjusted until two images on an image screen coincide with one another. The position of the movable mirror is sensed and utilized in a servo control system for positioning the ocular lenses at a focussed position. The distance to the object being viewed is displayed by providing an indicator attached to the ocular lens positioning mechanism.

Abstract: Binoculars including an eye span adjustment mechanism and an automatic focussing feature. A pair of guide rails is disposed laterally in the binoculars housing. Drive rods threadedly engaged with the lens barrels are movable along the guide rails to move the lens barrels back and forth in response to rotation of a knob and adjustment rod. An automatic focussing is disposed between the lens barrel to move the ocular lens in response to an electronically produced focussing signal.

Abstract: Binoculars including an automatic focusing system with light entry windows on both sides of the binoculars provided outwardly of the objective lenses. Movable and fixed reflecting elements are disposed inwardly of the light entry windows both of which direct incoming light images onto a focusing detecting module. The movable reflector is oscillated back and forth scanning the image reflected thereby laterally with respect to the stationary image reflected by the fixed reflector. An output control signal is produced when the two images are in alignment with one another and the ocular lenses are moved in accordance with this signal to properly focus the binoculars.

Abstract: An apparatus is provided which produces an alarm signal when the magnitude of a varying physical quantity such as the running speed of an automobile, for example, exceeds one of a plurality of preset threshold values. The apparatus includes detection means having a plurality of detection channels in which mutually different threshold values are defined and capable of producing an electrical output in response to the magnitude of the varying physical quantity exceeding a threshold value in each of the detection channels; selection means for selecting one of the threshold values and for providing an output signal indicative of the selected threshold value; and comparison and control means for comparing the output from the detection means and the output from the selection means to produce an electrical output when the magnitude of the physical quantity exceeds the threshold value selected by the selection means.

Abstract: A process for heat-bonding optical fibers comprising aligning a number of optical fibers in a mould with at least one of whose end surfaces is open and with end members slidable towards the inside of the mould from positions at which the end surfaces are open whereby a gas present among the optical fibers can be discharged, heating the optical fibers and evacuating the gas in the mould, closing the open end surfaces and applying pressure to the optical fibers through a press member and the end members, thereby heat-bonding the optical fibers; and an apparatus for heat-bonding optical fibers, comprising a mould with at least one of whose end surfaces is open, and including a press member as a wall of the mould, at least one end member provided for the end surfaces of the mould, and being capable of sliding inwardly along inclined surfaces of the press member upon application of a presssure on the press member.

Abstract: A process for producing a gas tight light transmitting optical fiber plate comprising arranging the optical fibers or bundles of the optical fibers in a die, heating and compressing the optical fibers at a temperature of between the transition point of the glass of the optical fibers and the softening point of the glass of the optical fibers thereby to weld the optical fibers together, and maintaining the welded optical fibers within that temperature range at a pressure higher than the pressure during the heating period which is sufficient to cause the shrinkage of voids by the surface tension of the optical fibers.