Abstract: The invention relates to an automatic focusing mechanism for an operation microscope. In the apparatus in accordance with the invention, when the position and angle of the operation microscope is altered by the operator, a constant moving margin is always secured so that the automatic focusing mechanism has sufficient room to perform the focusing function. This is accomplished by setting an optional origin position within the moving range of the drive objective section of the operation microscope. When the operation microscope is brought to a free condition by a switch section, a driver mechanism operates so as to return the drive objective section to the location of the origin position. Thus, when the position and angle of the microscope is altered, a constant moving margin of the drive objective section is always maintained. Thus, the location of the drive objective section always has sufficient room to perform the automatic focusing function.

Abstract: The invention provides a stand apparatus for a medical optical instrument, in which a rear-side parallel link mechanism and a counterweight are arranged below those of a conventional arrangement.The rear-side parallel link mechanism having the counterweight is arranged below that of the conventional arrangement, and operation of a front-side parallel link mechanism is transmitted to the rear-side parallel link mechanism through a transmission mechanism. Accordingly, a weight balance of the medical optical instrument is surely tried by the counterweight similarly to the conventional arrangement. Further, an upper rear space, which has conventionally been occupied by the rear-side parallel link mechanism, can freely be used by an operator and an assistant and, therefore, this becomes very convenient. Furthermore, a position of the center of gravity of the entire stand apparatus is lowered considerably, and stability of the stand apparatus increases.

Abstract: In a stand apparatus for a medical optical instrument, a first link mechanism including a first pantograph arrangement has a proximal end which is mounted on a body having a horizontal groove. The body is rotatable about a vertical axis. The first pantograph arrangement has an intermediate section which is slidably engaged within the horizontal groove. The first pantograph arrangement reciprocating linearly along a horizontal direction has a forward end on which a horizontal moving element having a vertical groove is mounted. A second link mechanism including a second pantograph arrangement has a proximal end which is mounted on the horizontal moving element. The second pantograph arrangement has an intermediate section which is slidably engaged within the vertical groove in the horizontal moving element. The medical optical instrument is supported at a forward end of the second pantograph arrangement which reciprocates linearly along a vertical direction.