Abstract: An image fiber includes plural kinds of cores and a common cladding containing the cores, which are arrayed so that no similar cores are adjacent one another. A method of making the image fiber is that a plurality of optical fiber elements having cores of different diameters are arranged so that no similar cores are adjacent one another, and after being inserted in a jacket pipe, are heated at a high temperature to fuse the cladding portions of the optical fiber elements so that the whole is drawn down to a desired thickness.

Abstract: N lines of line-shaped light are projected onto the object by means of a measuring light projecting lens. The light carrying the image of the object is passed through the eyepiece lens 17 in an endoscope 6 and the auxiliary lens 30 in a measuring head 11 and split into two beamlets by a beam splitter 31, with one beamlet being focused at a position coinciding with the entrance end faces of measuring light's position detecting fibers 33(l) to 33(m). The line-shaped light images of the object thus formed in positions coinciding with the entrance end faces of measuring light's position detecting fibers 33(l) to 33(m) are scanned linearly by those linearly aligned fibers as they are oscillated and driven by a fiber scanner 36. The scanned line-shaped light images are then subjected to the necessary signal processing in a signal processor circuit 35 such as to measure the three-dimensional configuration of the object.

Abstract: An image fiber has a plurality of optical fibers with normalized frequencies different from one another, which is constructed so that a plurality of cores different in size and shape from one another are distributed at random in a cladding. The optical fibers include at least two kinds of optical fibers having propagation modes different in number. Thus, the image fiber is capable of suppressing cross talk to prevent the degradation of image quality.

Abstract: An observation system for an endoscope has an entrance end face upon which an image is incident and an exit end face from which the image exits. The system comprises an image guide fiber of a very small diameter to allow transmission of the image, an object optical system arranged in front of the entrance end face of the image guide fiber, and a reproduction optical system arranged on the back side of the exit end face of the image guide fiber. The reproduction optical system is comprised of an eyepiece optical system and relay lens system. The maximal exit numerical aperture of the object optical system is greater than the maximal entrance numerical aperture of the reproduction optical system.

Abstract: An objective lens system for endoscopes comprising, in the order from the object side, a first lens component having a negative refractive power, a second lens component having a positive refractive power, an aperture stop arranged right after the second lens component, and a rear lens unit comprising a third lens component designed as a cemented doublet consisting of a lens element having a positive refractive power and a lens element having a negative refractive power. Said objective lens system for endoscopes has a wide field angle, a compact design, a small number of lens elements and favorably corrected aberrations.

Abstract: An imaging apparatus is provided with a negative lens, a variable focussing lens unit including a material with an electrooptic effect, a light blocking unit, including the material with the electrooptic effect, capable of changing an aperture diameter, and a switch, interlocked with each other, capable of supplying electric power to the variable focussing lens unit and the light blocking unit which are arranged in order on an optical axis from an object side to an image side. When the switch is turned off, the variable focussing lens unit is set to bring an object at a far point into focus and the light blocking unit is set so that an aperture is determined by an aperture stop, while on the other hand, when the swtich is turned on, the variable focussing lens unit is set so that an object at a near point is in focus and the light blocking unit is set to be smaller in aperture.

Abstract: An imaging apparatus is provided with a negative lens, a variable focal length lens unit including a material with an electrooptic effect, a light blocking unit, including the material with the electrooptic effect, capable of changing an aperture diameter, and a switch, interlocked with each other, capable of supplying electric power to the variable focal length lens unit and the light blocking unit which are arranged in order on an optical axis from an object side to an image side. When the switch is turned off, the variable focal length lens unit is set to bring an object at a far point into focus and the light blocking unit is set so that an aperture is determined by an aperture stop, while on the other hand, when the switch is turned on, the variable focal length lens unit is set so that an object at a near point is in focus and the light blocking unit is set to be smaller in aperture.