Surgery – Endoscope – Having imaging and illumination means
Reexamination Certificate
2000-09-28
2002-09-10
Leubecker, John P. (Department: 3739)
Surgery
Endoscope
Having imaging and illumination means
C600S168000, C600S129000
Reexamination Certificate
active
06447447
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Art
This invention relates to an endoscope for use in medical examinations, and more particularly to an endoscope which is provided with an objective lens drive mechanism to move by remote control a plural number of lens groups of an optical objective lens system, which is incorporated into an observation window on a rigid tip end section of an elongated insertion instrument of the endoscope, for example, for adjustment of at least focal depth, image magnification rate or view field angle.
2. Prior Art
Generally, endoscopes which are in use for medical purposes are largely constituted by a manipulating head assembly to be gripped and manually operated by a hand of an operator, an elongated insertion instrument extended on the front side of the manipulating head assembly for insertion into a body cavity of a patient, and a universal cable which is led out from the manipulating head assembly and disconnectibly connected to a light source. For its functions, the elongated insertion instrument of an endoscope is successively constituted by, from its fore distal end, a rigid tip end section, an angle section and a flexible body portion. The flexible body portion occupies the major length of the elongated insertion instrument from a proximal end portion which is connected to the manipulating head assembly, and arranged to be bendable in arbitrary directions along a path of insertion. The rigid tip end section contains an illumination window or windows, an image pickup means, and an opening of a biopsy channel through which forceps or other instrument is introduced into a body cavity. The angle section is can be angularly bent by remote control from the manipulating head assembly, for turning the rigid tip end section into an arbitrary direction.
As mentioned above, the rigid tip end section contains at least an illumination window and an image pickup means. Located within the illumination window is a light emitting end of a light guide which is constituted by a bundle of fiber optics. The light guide is extended as far as the above-mentioned universal cable via the manipulating head assembly and disconnectibly connected to a light source. On the other hand, as the image pickup means, an optical objective lens system is fitted in an observation window on the rigid tip end section. In the case of an electronic endoscope, a solid-state image sensor device is located at the focus of the optical objective lens system. In the case of an optical endoscope, an image pickup end of a light guide, which is constituted by a bundle of fiber optics, is located at the focus of the optical objective lens system. A signal cable which is connected from the solid-state image sensor device or the image guide is passed through the insertion instrument along with the light guide and extended to the manipulating head assembly. An electronic endoscope which appears in the following description can be read and taken as an optical endoscope if a solid-state image sensor device and a signal cable is replaced by an image guide.
In addition to the above-mentioned component parts, an exit opening of a biopsy channel is provided on the rigid tip end section. Connected to the exit opening is a biopsy channel which is constituted by a flexible tube. Further, a wash nozzle is provided on the rigid tip end section to wash clean the observation window when contaminated. An air/water feed tube is connected to the wash nozzle. These biopsy channel and air/water feed tube are extended as far as the manipulating head assembly through the elongated insertion instrument of the endoscope.
As described above, an elongated insertion instrument of an endoscope is normally required to accommodate bundles of fiber optics, signal cable, biopsy channel and a number of feed tubes. In order to bend the angle section as described above, a pair of upper and lower operating wires or two pairs of vertical and horizontal operating wires are also passed through the insertion instrument. The fore ends of these operating wires are fixed either to the rigid tip end section or to a structural member in the proximity of the rigid tip end section. Within the angle section, the positions of the operating wires are restricted in circumferential direction. Further, the respective operating wires are extended as far as the manipulating head assembly through the flexible section of the endoscopic insertion instrument.
The optical objective lens system of the image pickup, which is normally constituted by a plural number of lenses, should preferably be capable of adjustments in focal depth, image magnification and view field angle, depending upon the position of an intracavitary portion to be examined or upon the purpose of examination. In this regard, it has been known to make part of the lenses of the optical objective lens system movable in the direction of optical axis for adjustments of focal depth, image magnification or view field angle.
As for drive means for moving a movable lens in the direction of optical axis of the objective lens system, there have been various proposals, including piezoelectric elements, shape memory alloys and artificial muscle. However, in actual applications, it has been the general practice to use a control cable for shifting the position of a movable lens or lenses by remote control. In such a case, the fore end of a control cables is connected to the movable lens, while the proximal end of the cable is extended into the manipulating head assembly in such a way that an operator can shift the position of a movable lens in the direction of optical axis by remote control from the head assembly. More particularly, a control cable of this sort is usually composed of a flexible sleeve and a number of transmission members which are fitted in the flexible tube. The transmission members are either in the form of push-pull type operating wires or in the form of a flexible rotation transmission shaft which is constituted by tightly wound coil tubes. In the case of push-pull wires, the fore end of operating wires are connected to a support member of a movable lens thereby to push or pull the movable lens. On the other hand, in the case of a flexible transmission shaft, a screw rod which is connected to the fore end of a flexible transmission shaft is engaged with a nut member which is provided fixedly on the part of a movable lens support member, for example, on a movable lens frame. Accordingly, in this case, a rotational movement of the flexible transmission shaft is translated into a linear movement of a movable lens. No matter whether the drive means employs the push-pull wires or a flexible transmission shaft, it can be arranged either as a manual drive or as a power drive having a motor or an actuator incorporated into a manipulating head assembly of an endoscope.
For instance, for varying an image magnification rate, it has been known to employ an objective lens system employing two lens groups, i.e., a variator lens and a compensator lens, which are movable in the direction of optical axis of the objective lens system independently of each other. In this instance, each one of the two lens groups is not necessarily composed of a plural number of lens elements, and can be composed of a single lens element. The two lens groups are moved in a different way from each other in distance, speed and direction. However, considering the smallness in diameter of the endoscopic insertion instrument, it has been found impossible to incorporate two independent drive means into the insertion instrument for the purpose of driving the two lens groups in different ways as mentioned above. In this connection, attempts have been made to provide movable lenses within a cam tube and to move a plural number of lenses concurrently in predetermined directions by rotating or linearly moving the cam tube, for example, as disclosed in Japanese Laid-Open Patent Application H11-42202. The drive mechanism according to this prior art employs a cam tube which is provided with a plural number of cam grooves in
Fuji Photo Optical Co., Ltd.
Leubecker John P.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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