Abstract: An endoscope suitable for autoclave sterilization includes an insertion section having an objective lens section disposed at the extreme end thereof for focusing a subject image and an eyepiece section located on the base end side of the inserting section and including at least an eyepiece lens. an image guide fiber is disposed in the bundle for transmitting the subject image in an observation section focused by the objective lens section. An eyepiece lens unit is disposed in the eyepiece section, the eyepiece lens unit causing the eyepiece lens to confront the base end structure whose hermetic seal level is higher than the watertight seal level of the shell of the endoscope. A focus position changing means is disposed to the eyepiece lens unit to change the focus position of the eyepiece lens. The eyepiece section is so constructed and/or assembled that the autoclave sterilization process does not cause water vapor or the like to adversely affect the operability of the eyepiece section.

Abstract: An endoscope includes an image pickup unit 30 having a solid-state image pickup device 32 such as a CCD on a tip end side of an elongate insertion section. This image pickup unit 30 constitutes a tip end side unit 36U and a rear end side unit 43U by conducting a surface treatment (metallization) to nonmetal members such as a tip end cover glass 31 and a rear end cover glass 35, and by airtight coupling surface-treated portions of the nonmetal members to metal members such as a tip end cover glass frame 36 and a rear end cover glass frame 43 by brazing using soldering, and constitutes an optical system unit 60 by airtight coupling the metal members to metal members of an insulating unit 38U formed by airtight coupling a pipe member 41 and a ring member 42 to an insulating frame 38 by welding.

Abstract: Method of controlling resistance welding to obtain high quality welds in which the pressure between the electrodes (2a, 2b) holding the materials (1a, 1b) to be welded is controlled so that the resistance value between the two electrodes (2a, 2b) is a predetermined value, and the welding current is regulated so that the voltage between the electrodes is a predetermined value, and the time during which the welding current flows is controlled to a fixed period.