System for positioning optical fibres in a telescope

Abstract

The invention relates to a system for positioning optical fibres (2) in a telescope, the system being characterised in that it comprises a plurality of modules (1) configured so as to be attached to the focal plate of a telescope; wherein each module (1) contains a plurality of optical fibre positioners (3), each primarily comprising an alpha motor (4) and a beta motor (5) that interact with one another so as to position the end of an optical fibre (2) inside a circular zone; and wherein each optical fibre positioner (3) is further formed of two subassemblies that are assembled in a module (1).

Description

[0001] System for positioning optical fibers in a telescope

[0002] Field of invention

[0003] The present invention relates to the positioning of optical fibers and more particularly to the positioning of optical fibers in a telescope.

[0004] State of the art

[0005] In prior art systems, as described in international patent application WO 2022 / 106983 A2, each optical fiber is positioned by means of a positioner which is in the form of an assembly individually mounted on the focal plate of the telescope. Each positioner comprises two rotary motors, alpha and beta, which interact with each other so as to position an optical fiber within a circular area.

[0006] General description of the invention

[0007] The invention itself relates to a system for positioning optical fibers in a telescope, characterized in that it comprises a plurality of modules configured to be fixed to the focal plate of a telescope. Each module contains several optical fiber positioners, each comprising mainly an alpha motor and a beta motor which interact with each other so as to position the end of an optical fiber within a circular area. Each optical fiber positioner is further formed of two subassemblies which are assembled in a module.

[0008] The assembly of each positioner in a module offers the advantage of using the space normally used for fixing the positioners (screws, etc.) directly on the focal plate. The modules are fixed on the focal plate of the telescope. To facilitate maintenance, they are preferably removable and interchangeable. The modules can also be tested and characterized before being mounted in a telescope.

[0009] Detailed description of the invention

[0010] In this chapter, the invention is described by means of non-limiting examples illustrated by the following figures:

[0011] Figure 1: Module according to the invention

[0012] Figure 2: Sectional view of the module in Figure 1

[0013] Figure 3: Cross-sectional view of the module in Figure 1

[0014] Figure 4: Introduction (respectively removal) of a positioner in a module

[0015] Figure 5: Using an annular spring for positioning or removing a positioner assembly

[0016] Figure 6: Ring spring

[0017] Figure 7: Using an annular spring to remove play in ball bearings

[0018] Figure 8: Example of a positioner formed from a tube

[0019] Figure 9: Use of a plain bearing

[0020] Figure 10: Arrangement of a leaf spring in a bore of the bearing of Figure 9

[0021] Figure 11: Integration of the blade of Figure 10 into the body of a positioner

[0022] Figure 12: Using a support finger

[0023] Figure 13: Using a flexible tab

[0024] Figure 14: Using a spring washer

[0025] Figure 15: Alpha motor stop Figure 16: Beta motor stop

[0026] Numerical references used in the figures:

[0027] 1. Module

[0028] 2. Optical fiber

[0029] 3. Positioner

[0030] 4. Alpha Engine

[0031] 5. Beta Engine

[0032] 6. Ring spring

[0033] 7. Alpha rear bearing

[0034] 8. Tube

[0035] 9. Alpha front landing

[0036] 10. Beta rear bearing

[0037] 11. Spring blade

[0038] 12. Linear spring

[0039] 13. Support finger

[0040] 14. Flexible tongue

[0041] 15. Cone

[0042] 16. Spring washer

[0043] 17. Alpha output pinion

[0044] 18. Alpha stop

[0045] 19. Intermediate piece

[0046] 20. Beta output pinion

[0047] 21. Beta stop

[0048] 22. Ball bearing

[0049] 23. Beta axis

[0050] Figure 1 represents a module 1 according to the invention which comprises a set of positioners 3.

[0051] In this example, module 1 has a roughly triangular section.

[0052] The invention is not limited to this type of geometry. Any other section that allows the desired goal to be achieved can be used. Preferably, the section of the modules 1 (most often polygonal) is chosen so as to avoid the presence of empty spaces between the modules 1.

[0053] Each positioner 3 (see figures 2 and 3) is mainly made up of an alpha motor 4 and a beta motor 5. Each positioner 3 is crossed by an optical fiber 2. The operation of the positioners 3 is similar to the positioners described in application WO 2022 / 106983 A2.

[0054] Each end of optical fiber 2 (see figure 3) is positioned individually so as to capture the light coming from the objects to be observed (stars, galaxies, etc.). The position of the optical fibers 2 is adjusted according to the configuration of the objects to be observed.

[0055] According to an embodiment of the module according to the invention 1 shown in Figures 4 to 6, an annular spring 6 (e.g. Bal Spring®) is used to axially hold the positioner 3 in the chassis of the module 1. Once the positioner 3 is in place, the annular spring 6 is arranged between two ball bearings 22 which form the rear bearing of the alpha motor 7 (see Figure 7). The use of this spring 6 allows disassembly of the positioner 3 if necessary (e.g. replacement of a defective positioner).

[0056] The annular spring 6 may also or alternatively serve to remove play in the ball bearings 22 of the rear bearing of the alpha axis 7, as shown in Figure 7.

[0057] According to another embodiment of the invention (see Figure 8), the body of the positioner 3 has an external casing in the form of a tube 8, which makes it possible to obtain a rigid assembly with minimal bulk. There is sufficient space inside the tube 8 to house the beta motor 5 and to pass the optical fiber 2. The optical fiber 2 is protected by the tube 8, cannot come into contact with toothed wheels or become tangled.

[0058] If there is insufficient space to accommodate ball bearings, plain bearings can be used. In this type of configuration, various mechanisms for taking up bearing play can be considered.

[0059] In the example of figures 9 to 11, a spring blade 11 is integrated into the body of the positioner 3. The front bearing of the alpha motor 9 is a plain bearing. To obtain sufficient precision, the spring blade 11 rests in the bore of the frame of the positioner 3 (see figure 10) and thus compensates for the lateral play.

[0060] In the example of Figure 12, the beta axis 23 also uses plain bearings. The lateral play is taken up by a finger 13 on spring 12, which exerts a transverse force on the beta axis 23 and thus eliminates the lateral play.

[0061] In the variant illustrated in Figure 13, the lateral play is taken up by a flexible tongue 14, which rests on a conical element 15 arranged around the beta axis 23.

[0062] In the variant illustrated in figure 14, the lateral play is taken up by a spring washer 16, which rests on a conical element 15 arranged around the beta axis 23.

[0063] Preferably, the rotation of the positioner 3 should be limited, e.g. by means of stops, to prevent damage to the optical fiber 2 in the event of excessive rotation. When starting the system, the stops can be used as reference positions.

[0064] In the examples illustrated in figures 15 and 16, the stops alpha 18 and beta 21 are located near their respective motors 4, 5, that is to say directly on their output pinions 17, 20. Such configurations have the advantage of not requiring a significant part of the mechanics of the positioner 3 when the system interacts with the stops 18, 21. On the alpha 4 motor an intermediate part 19 is added between the output pinion 17 and the end of the alpha 4 motor in order to allow a deflection a = ai + a2 greater than 360°. This part 19 is not necessary on the beta 5 motor, whose deflection 0 is less than 360°.

Claims

Claims 1. System for positioning optical fibers (2) in a telescope characterized in that it comprises a plurality of modules (1) configured to be fixed on the focal plate of a telescope; each module (1) containing several optical fiber positioners (3) each mainly comprising an alpha motor (4) and a beta motor (5) which interact with each other so as to position the end of an optical fiber (2) inside a circular area; system in which each optical fiber positioner (3) is further formed of two sub-assemblies which are assembled in a module (1).

2. System according to claim 1 in which each positioner (3) is positioned by means of an elastic element (e.g. a spring), preferably of annular shape (6).

3. System according to claim 1 or 2 in which the body of each positioner (3) is formed from a tube (8) of preferably circular section.

4. System according to one of claims 1 to 3 in which the positioner (3) comprises at least one spring element, preferably a blade (11), configured so as to act as a take-up mechanism.

5. System according to one of claims 1 to 3 in which the positioner (3) comprises at least one flexible tab (14) configured so as to act as a catch-up mechanism.

6. System according to one of claims 1 to 3 in which the positioner (3) comprises at least one spring washer (16) configured so as to act as a take-up mechanism.

7. System according to one of claims 1 to 3 in which the positioner (3) comprises a support finger (13) on a spring (12) configured so as to act as a catch mechanism.

8. System according to one of the preceding claims in which the alpha motor (4) comprises an output pinion (17) and at least one stop (18) configured so as to limit the rotation of the alpha motor (4), said stop (18) being integrated on the output pinion (17).

9. System according to one of the preceding claims in which the beta motor (5) comprises an output pinion (20) and at least one stop (21) configured so as to limit the rotation of the beta motor (5), said stop (21) being integrated on the output pinion (20).

10. Module as defined in one of the preceding claims formed from a tubular element of triangular section and comprising a set of passages configured to house optical fiber positioners (3).

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