Optical measuring element having a single-piece structure
An optical measuring element measures forces in at least one direction. The measuring element has a single-piece structure. There is an outside wall with notches introduced therein. Each notch defines parallel edges, and the notches define more or less elastically flexible zones in the structure and constitute the only connection between a first region and a second region of the structure. For optical distance measurements between the two regions of the structure, one or more optical fibers are each attached with one end thereof to a region of the structure such that reflective surfaces are located close to the ends. The reflective surfaces are firmly connected to another region. The optical fibers are disposed on the outside wall.
1. An optical measuring element for measuring forces in at least one direction wherein said measuring element comprises a single-piece structure that elongates in a longitudinal direction with an outside wall and with at least two notches introduced therein wherein said notches define an elastically flexible zone in the structure being the only connection between a first region and a second region of the structure spaced apart, and wherein for optical distance measurements between the two regions of the structure at least one optical fiber is attached with one end thereof to one of the regions of the structure such that close to the end of said optical fiber a reflective surface is located which is firmly connected to the other of the two regions, wherein the optical fiber is disposed at the outside wall and that each notch consists of parallel edges within the structure in way that the edges the surrounding the notch within the structure are defined by parallel straight lines within the structure, all such lines being parallel to themselves.
2. A measuring element according to claim 1 wherein each notch penetrates the whole structure to the outside wall.
3. A measuring element according to claim 1 , further comprising at least a second optical fiber disposed for optical distance measurements between two distinct regions of the structure.
4. A measuring element according to claim 3 wherein the structure is subdivided by several connections having elastically flexible zones in at least three distinct regions.
5. A measuring element according to claim 4 wherein between each two adjacent regions at least one optical fiber for optical distance measurements is disposed at the structure.
6. A measuring element according to claim 4 wherein each connection between two adjacent structures is formed by an elastically flexible zone that allows for deformations in only one of the directions x, y, and z.
7. A measuring element according to claim 6 wherein the structure is subdivided by three connections into four regions arranged in series wherein a first connection is formed by an elastically flexible zone that allows for deformations in the x direction only, a second connection is formed by an elastically flexible zone that allows for deformations in the y direction only, and a third connection is formed by an elastically flexible zone that allows for deformations in the z direction only.
8. A measuring element according to claim 1 , wherein at least one of the connections is formed by an elastically flexible zone that will allow for deformations in at least two of the directions x, y, and z.
9. A measuring element according to claim 8 wherein at least two optical fibers are arranged for optical distance measurements between the two regions of the structure.
10. A measuring element according to claim 1 , wherein the structure is a hollow body having a central cavity.
11. A measuring element according to claim 1 , wherein the structure has a diameter of less than 2.5 mm.
12. A measuring element according to claim 1 , wherein the optical distance measurement can be measured by an interferometric measurement principle.
13. A measuring element according to claim 1 , wherein each optical fiber consists of a pair of optical fibers for photometric measurements.
14. A measuring element according to claim 1 , wherein the structure is surrounded at least in the region of the connections by a membrane sheath for sealing.
15. A measuring element according to claim 1 , further comprising an overload protection that prevents the end of the optical fiber from contacting the opposite reflective face in case of an overload and/or prevents an irreversible deformation of the structure.
16. A measuring element according to claim 1 , wherein the structure is made of a conductive ceramic or of a semiconductor material.
17. The use of a measuring element according claim 1 , wherein such use is for invasive and/or minimally invasive medical purposes.
18. The use of the measuring element according to claim 1 , wherein the optical distance measurement is carried out using an interferometric measurement principle,
19. A measuring element according to claim 1 , wherein the structure is made of silicon.
20. The use of the measuring element according to claim 1 , wherein the optical distance measurement is carried out using white light interferometry.