ENDOSCOPE

Abstract: An endoscope (1) for use in minimally invasive surgery, comprises an inspection tube (2), provided with a light source (8). A lens (3) is positioned on an angularly adjustable lens holder (4) at the distal part of the inspection tube (2). A control organ (5), at the proximal end of the inspection tube (2) is coupled with the lens holder (4) for its adjustment in relation to the inspection tube. The light source (8) is positioned near the distal end at such a distance from the lens holder (4), that silhouettes perceivable by the lens (3) can be formed.

Description: Endoscope The invention relates to an endoscope for use in minimally invasive surgery, comprising an inspection tube, which is provided with a light source and which at its distal end opens into a lens . Such an endoscope is known, for example, from the article Human sense of vision : a guide to future endo- scopic imaging systems by the authors M.O. Schurr, G. Buess, E. Kunert, E. Fleming, H. Henmeking and L. Gumb, published in Minimally Invasive Therapy and Allied Technologies; 1996; No. 5, p. 410-418. The endoscope disclosed in this article is formed as a straight inspection tube with the lens looking ahead. Around the lens light conductors are provided for the illumination of the object to be inspected. The image obtained by such an endoscope is projected onto a monitor in order to provide the surgeon with visual information during the performance of the minimally invasive surgery. However, this type of the imaging entails problems with regard to the perception of distances and movements perpendicularly to the focal plane. A first problem is that the surgeon accommodates to the focal plane of the monitor and not to the actual objects. Depth perception is therefore problematic. A further problem is that although the light source mounted around the lens provides a brighter image, it has an adverse effect on the surgeon's depth perception because of the absence of shadows . An endoscope according to the preamble of claim 1 is known from US-A-3 , 572 , 325. In the endoscope known from US-A-3 , 572 , 325 the lens is positioned in the plane of the lens holder connected to the inspection tube, which lens holder is adjustable at an angle in relation to a substan- tial part of the inspection tube. This feature makes it possible for the lens together with the light source to be repositioned without moving the inspection tube of the endoscope, so as to allow the image on the monitor connected to the endoscope to change in a natural manner. The adjustability of the lens holder with respect to the inspec- tion tube thus provides an additional degree of freedom. The measures of freedom provided by said known endoscope are : 1. rotation of the inspection tube; 2. movement of the inspection tube coaxially with the endoscope; 3 and 4. Movement of the lens holder in the plane of viewing 5. the adjustability of the lens holder in respect of the inspection tube. A sixth measure of freedom may be formed by the possibility to rotate the lens holder around its axis. This movement may optionally also be effectuated by video- processing of the image that can be obtained with the known endoscope. The endoscope according to the invention is characterized in that the light source is positioned near the distal end at some distance from the lens holder, such that there is sufficient distance from the light source to the lens to form silhouettes which the lens is able to perceive. Using a light source in such a manner assists the endoscope ' s depth perception due to the shadow effect created as a result of the positioning of the light source . It is further desirable that the light source in relation to the inspection tube be adjustable at an angle. In this way the shadow effect can always be obtained for the respective direction of viewing. It is further advantageous for the light source to be adjustable simultaneously with the lens holder, to avoid the necessity of separate adjustment devices for operating the light source and the lens holder. Desirably the lens holder is continuously adjustable in relation to the inspection tube between a ) ) t H H Lπ o σι o cπ O U1 ranged between and coupled with the lens holder, such that the lens holder follows every movement of the handle. In this way the movement of the handle may be coupled directly with the lens holder, providing a one-to-one cou- pling between lens holder and handle. Conveniently, the handle may be shaped like an arrow. In this way the surgeon is able to obtain information regarding the viewing direction of the endoscope, whatever the position of the endoscope . The invention will now be elucidated with reference to the drawings, which in Figures la to lc show a very schematic representation of the endoscope according to the invention in three possible positions; and in Figure 2, schematically shows a few mechanical design aspects of the endoscope according to the invention. Identical reference numbers used in the figures refer to similar parts. The endoscope in the figures is generally indicated by reference number 1. Said endoscope 1 comprises an inspection tube 2 through which image signals are conveyed. The distal end of the inspection tube 2 opens into a lens 3. The lens 3 is positioned on a lens holder 4 con- nected with the inspection tube 2, which lens holder 4 can be adjusted at an angle in relation to the inspection tube 2. The images received via the lens 3 are processed further in the usual manner. For example, the lens 3 may be part of a camera that converts the image data into elec- tronic signals. These electronic signals are subsequently processed in the usual manner and displayed on a video display unit. The person skilled in the art is quite familiar with this and there is no need for any further explanation. The lens holder 4 is continuously adjustable in relation to the inspection tube 2 between a first position in the extended direction of the inspection tube 2, and a second position in which the lens holder 4 forms an angle t 0 tr Φ Pi i ι_ι. 3 01 rr φ i P ) rr rr tr Φ 01 0 ) 3 φ rr μ- 3 φ

Claims: CLAIMS 1. An endoscope (1) for use in minimally invasive surgery, comprising an inspection tube (2), which is provided with a light source (8) and which at its distal end opens into a lens (3) which is positioned on a lens holder (4) , which lens holder (4) is adjustable at an angle in relation to a substantial part of the inspection tube (2) , to which end the inspection tube at its proximal end is provided with a control organ (5) , which is coupled with the lens holder (4) for its adjustment in relation to the inspection tube (2) , characterized in that the light source (8) is positioned near the distal end at some distance from the lens holder (4) , such that there is sufficient distance from the light source (8) to the lens (3) to form silhouettes which the lens (3) is able to perceive . 2. An endoscope according to claim 1, characterized in that the light source (8) in relation to the inspection tube (2) is adjustable at an angle. 3. An endoscope according to claim 1 or 2 , characterized in that the light source (8) is adjustable simul- taneously with the lens holder (4) . 4. An endoscope according to one of the claims 1- 3, characterized in that the lens holder (4) is continuously adjustable in relation to the inspection tube (2) between a first position in the extended direction of the inspection tube (2) and a second position in which the lens holder (4) forms an angle of approximately 110° in relation to the inspection tube (2) . 5. An endoscope according to one of the preceding claims, characterized in that the control means is a han- die (5) , which is coupled with the lens holder (4) by means of the inspection tube (2) and by means of a separate adjustment coupling. 6. An endoscope according to claim 5, character- ized in that the handle (5) and the lens holder (4) are coupled cardanically with the inspection tube (2) , and in that the adjustment coupling comprises control wires (6,7) arranged between and coupled with the handle 5 and the lens holder (4) , such that the lens holder (4) follows every movement of the handle (5) . 7. An endoscope according to claim 5 or 6, characterized in that the handle (5) is shaped like an arrow.

Inventors: BREEDVELD PAUL, BREEDVELD, PAUL
Applicants: BREEDVELD PAUL, UNIV DELFT TECH, BREEDVELD, PAUL, TECHNISCHE UNIVERSITEIT DELFT
Application year: 2000
Main classification: A61B1
IPC codes: A61B1, G02B23