Medical endoscopic instrument

1 . A medical endoscopic instrument comprising:

a distal elongated insertion section configured for minimally invasive insertion into a human or animal body;

a LED arranged in a distal end section of the insertion section;

a lens system arranged distally of the LED, the lens system having an optical axis, wherein the lens system comprises a first lens and a second lens arranged distally of the first lens, and wherein the second lens includes a proximally extending sleeve extension and wherein the first lens includes a sleeve extension with a distal section and a proximal section, wherein the sleeve extension of the second lens includes a first reference surface for positioning the second lens in relation to the insertion section and a second reference surface for positioning the first lens in relation to the second lens, wherein the second lens is a plano-concave lens with a planar surface, the planar surface of the second lens facing in a proximal direction; and

a shortpass filter being arranged at the planar surface of the second lens, wherein the sleeve extension of the second lens surrounds the shortpass filter, the first lens, the LED and the distal section of the sleeve extension of the first lens.

2 . The medical endoscopic instrument according to claim 1 , wherein the sleeve extension of the second lens is configured in one-piece with the second lens as an integral part of the second lens, the second lens being located at a first distance from an end of an end section of the insertion section, the first lens being located at a second distance from the end of the end section of the insertion section, the first distance being less than the second distance.

3 . The medical endoscopic instrument according to claim 1 , wherein the sleeve extension of the second lens extends longer, by a factor of 2 or more in an axial direction, than an axial thickness of the second lens on the optical axis, the shortpass filter being arranged between the first lens and the second lens.

4 . The medical endoscopic instrument according to claim 1 , wherein the first lens forms a distally acting abutment which is axially supported against the second reference surface of the sleeve extension of the second lens.

5 . The medical endoscopic instrument according to claim 1 , wherein the LED is circumferentially surrounded by the sleeve extension of the first lens.

6 . The medical endoscopic instrument according to claim 1 , wherein the sleeve extension of the second lens is produced by removing a core of a blank by means of an ablative process.

7 . The medical endoscopic instrument according to claim 1 , wherein the sleeve extension of the second lens is produced by means of an additive process.

8 . The medical endoscopic instrument according to claim 1 , wherein the sleeve extension of the second lens is produced by a combined additive and ablative process.

9 . The medical endoscopic instrument according to claim 1 , wherein the first lens is a converging lens and the second lens is a diverging lens.

10 . The medical endoscopic instrument according to claim 1 , wherein the shortpass filter is arranged between the first lens and the second lens.

11 . The medical endoscopic instrument according to claim 1 , wherein the first lens is a plano-convex lens.

12 . The medical endoscopic instrument according to claim 1 , wherein the first lens is planar towards the LED.

13 . The medical endoscopic instrument according to claim 1 , wherein the first lens and/or the second lens is/are a Fresnel lens.

14 . The medical endoscopic instrument according to claim 1 , wherein the proximal section of the sleeve extension of the first lens comprises an abutment, the abutment comprising an abutment surface, the sleeve extension of the second lens comprising an end portion, the end portion comprising an end surface, the abutment surface facing in a direction of the end surface.

15 . A method of producing a lens system, which is suitable for use in a distal end of a medical endoscopic instrument and comprises at least one lens, wherein a sleeve extension of the at least one lens is created by removing a core of a blank by means of an ablative process, the medical endoscopic instrument comprising a shortpass filter and a distal elongated insertion section, wherein the lens system further comprises another lens arranged distally of the at least one lens, the another lens including a proximally extending sleeve extension and wherein the sleeve extension of the at least one lens includes a distal section and a proximal section, wherein the proximally extending sleeve extension includes a first reference surface for positioning the another lens in relation to the insertion section and a second reference surface for positioning the at least one lens in relation to the another lens, wherein the another lens is a plano-concave lens with a planar surface, the planar surface of the another lens facing in a proximal direction, the shortpass filter being arranged at the planar surface of the another lens, wherein the sleeve extension of the another lens surrounds the shortpass filter, the at least one lens, an LED and the distal section of the sleeve extension of the at least one lens.

16 . A method of producing a lens system, which is suitable for use in a distal end of a medical endoscopic instrument, with at least one lens and a sleeve extension, wherein in a first additive step, quartz glass particles are mixed with a certain quantity of liquid plastic and, by way of stereolithography, are hardened by means of light at desired points, and a core of a blank in a form of material that had remained liquid, is then washed out in a solvent bath in a second ablative step so only a desired, hardened structure is left as the at least one lens with the sleeve extension, the medical endoscopic instrument comprising a shortpass filter and a distal elongated insertion section, wherein the lens system further comprises another lens arranged distally of the at least one lens, the another lens including a proximally extending sleeve extension and wherein the sleeve extension of the at least one lens includes a distal section and a proximal section, wherein the proximally extending sleeve extension includes a first reference surface for positioning the another lens in relation to the insertion section and a second reference surface for positioning the at least one lens in relation to the another lens, wherein the another lens is a plano-concave lens with a planar surface, the planar surface of the another lens facing in a proximal direction, the shortpass filter being arranged at the planar surface of the another lens, wherein the sleeve extension of the another lens surrounds the shortpass filter, the at least one lens, an LED and the distal section of the sleeve extension of the at least one lens.

17 . The method according to claim 16 , wherein the liquid plastic still mixed into the desired, hardened structure is removed by heating.

18 . The method according to claim 16 , wherein through a final sintering process, the desired, hardened structure is heated to such an extent that the glass particles melt and fuse together.

19 . The method according to claim 16 , wherein, through removal of the core of the blank, the at least one lens acquires a pot-shaped form which has an optically effective pot base and a mechanically effective circumferential pot wall.

20 . The method according to claim 19 , wherein an inner surface of the pot base can be ablated in a planar manner.

21 . The method according to claim 20 , wherein a light filter is attached to the inner surface of the pot base.

22 . The method according to claim 19 , wherein an outer surface of the pot base can be ablated in an arched manner.

23 . The method according to claim 16 , wherein the proximally extending sleeve extension of the another lens of the lens system is produced by removing a core of a blank by means of an ablative process.

24 . The method according to claim 23 , wherein the at least one lens and the another lens are arranged coaxially with regard to each other and at least partially in axial direction fastened to each other in an interlocking manner as the lens system, and the lens system is fitted into the distal end of the medical endoscopic instrument.