DE8634364U1 - Adjustment device for an optical element - Google Patents

Description

"··"·· · ^: ·· ^: - *··86·6 18890&Egr; Siemens Aktiengesellschaft

Adjustment device for an optical element

The innovation relates to an adjustment device for an optical element, in particular for a reflector mirror of an optical resonator, which is arranged on a carrier which is adjustable relative to a base body having a reference surface or a reference element by means of at least one adjustment screw designed in the manner of a differential screw, which has on its shaft two threaded areas lying one behind the other with different thread pitches, of which one threaded area is screwed into the carrier and the other threaded area is screwed into the base body.

In optical arrangements, e.g. for generating or amplifying coherent radiation (laser), the optical elements, i.e. in the case of a laser, the reflector mirrors of the optical resonator, must be adjusted as precisely as possible parallel to one another. Adjustment must be possible in very small angular ranges (arc second range) and the adjustment or setting of an optical element once made must be retained over a longer period of time, regardless of mechanical and/or thermal influences.

Known adjustment devices are usually constructed in such a way that the carrier of the optical element is connected to the base body via an elastic intermediate piece and can be adjusted using generally three screws arranged at the corners of a triangle and acting against the base body. Such a

Adjustment device is known e.g. from DE-OS 31 30 420.

Three counter screws are provided between the adjustment screws and are arranged at the corners of a triangle. The counter screws fix the position of the optical element so that it is vibration-proof. However, the adjusted position of the optical element is slightly changed immediately after it has been adjusted. However, the lack of counter screws means that the adjustment of a

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optical element is retained for a moment, but not over a longer period of time. This disadvantage occurs particularly in the case of mechanical and/or thermal influences.

Another holding device for laser mirrors is from the

DE-OS 33 28 34?. Here, the base body and mirror carrier are connected to one another via an elastic intermediate piece, whereby the adjusting screws, which are arranged at the corners of a triangle, are inserted into a flange of the mirror carrier and screwed into threaded holes in the base body. The adjusting screws are designed and/or arranged to be self-locking and are provided with a fine thread or self-holding braking means. This is intended to create an easily adjustable holding device that enables the mirror to be set at an exact and permanent angle relative to the base body. However, when using conventional adjusting screws, it is not possible to achieve precise fine adjustment of an optical element in very small angle ranges.

Furthermore, DE-PS 17 64 815 discloses an adjustable holder for the mirror of a gas laser, in which the adjusting screws are designed like a differential screw and have threaded parts with two different pitches on their shaft, one behind the other, one part of which is screwed into an adjusting flange supporting the mirror and the other part into a closure plate attached to the laser tube. This enables precise fine adjustment in very small angle ranges. However, the known holder does not have any counter elements, so there is a risk of adjustment and the adjustment is not sufficiently vibration-proof. A stable angle setting even over a long period of time is therefore not guaranteed.

The innovation is therefore based on the task of designing an adjustment device of the type mentioned above in such a way that the most accurate and play-free fine adjustment of an optical element is achieved in very small angular ranges and that the

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adjustment made both immediately after setting and

even over a longer period of time and regardless of mechanical and/or thermal influences.

This task is solved in an adjusting device of the type mentioned at the beginning according to the innovation in that a self-locking »••&bgr;&eegr;&sfgr;&EEgr;&iacgr;,&tgr;,&EEgr;&ogr;&iacgr;&bgr;&tgr; Cnwinring insert made of wire is provided between the threaded hole in the carrier and in the base body and the two threaded areas of the adjusting screw.

Thread inserts are already known for other purposes. Thread inserts are generally used to produce wear-resistant threads in metallic and non-metallic materials and to renew worn, damaged or unusable threads. In an adjustment device according to the innovation, however, the thread insert is not intended as a thread repair agent, but instead of locking the adjusting screws with conventional locking agents. The thread insert is therefore a type of replacement for a locking device and enables play-free and - in conjunction with the adjusting screw designed like a differential screw - precise fine adjustment of the optical element in very small angular ranges. The adjustment once ^made is retained without locking immediately after the adjustment process and also over a longer period of time and regardless of mechanical and/or thermal influences. This is achieved by the self-locking design of the thread insert.

In an adjustment device according to the innovation, it is advantageous if the threaded insert is shaped like a spiral spring and is self-locking by at least one straight wire part. The self-locking of the threaded insert is thus made possible without additional means simply by appropriate

Design of the threaded insert achieved. An advantageous embodiment of an innovative

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The adjustment device is described in more detail below using the drawing.

FIG 1 shows the principle of the adjustment device in section, FIG 2 and 3 a threaded insert in side and front view respectively

and

FIG 4 shows the wire cross-section of the threaded insert in an enlarged view.

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The device according to Figure 1 comprises a plate-shaped support

for an optical element 2, in particular for a reflector mirror of a laser resonator, for example fastened by gluing or clamping, and a base body 3, which is also plate-shaped and is connected to the carrier only via an elastic intermediate web 4 and has a reference surface 5 to which the optical element is adjusted. The base body 3 is arranged stationary here and can, for example, form an end plate of a gas laser tube, the reference surface 5 of which runs parallel to the other reflector mirror of the laser resonator. A screw 6 designed in the manner of a differential screw is provided as an adjusting screw, which is expediently made of the same material as the carrier and base body, e.g. of stainless steel, and is screwed into the area of the carrier 1 and the base body 3 which is approximately diagonally opposite the intermediate web 4. For this purpose, the adjusting screw 6 has two threaded areas 7 and 8 on its shaft, one behind the other, with different thread pitches, of which the threaded area with the smaller diameter and the smaller pitch is designed, for example , as an M4 thread and is screwed into a threaded bushing 9 arranged in the carrier 1 in a rotationally secured manner, made of the same material as the carrier, base body and adjusting screw and having an internal thread 18, while the other threaded area 8 with the larger diameter and the larger pitch is designed, for example, as an M5 thread and is screwed into a threaded hole 10 in the base body 3. Between the two threaded areas 7 and 8, the shaft of the adjusting screw 6 is designed as a neck 11 with a cross-section that is significantly tapered compared to the thread diameters, which compensates for the bending that occurs when the angle changes.

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tensions or stresses when adjusting the adjusting screw. The free end 12 of the adjusting screw 6 protruding from the base body 3 is designed so that the adjustment of the adjusting screw can be carried out as easily as possible. Here, the adjusting screw is provided with a hole 13. Instead of a counter, a threaded insert 14 or 15 made of wire is provided in both thread areas 7 and 8 of the adjusting screw, i.e. between the internal thread 18 of the threaded bush 9 and the thread area 7 of the adjusting screw 6 there is a threaded insert 14 adapted to an M4 thread, for example, and between the threaded hole 10 of the base body 3 and the thread area 8 of the adjusting screw there is a threaded insert 15 adapted to an M5 thread, for example. The thread inserts 14, 15 are shaped like a spiral spring (Figure 2) and are self-locking by at least one straight wire part 16 (Figure 3). The cross-section of the wire 17 used (Figure 4) is adapted to the shape of the thread. By using a differential screw as an adjusting screw with self-locking thread inserts, the adjusting device shown and described enables precise fine adjustment of an optical element in every position without play or jamming.

The principle of adjustment for one axis is shown in Fig. 1. An adjustment about a second axis can be achieved by connecting the arrangement according to Fig. 1 in series. In such an arrangement, an intermediate plate is to be provided instead of the base body, which in turn is to be connected to the base body downstream of it via an elastic second intermediate web and a second adjusting screw.

The two intermediate webs are provided in opposite edge areas of the support and the intermediate plate or the intermediate plate and the base body, running perpendicular to each other, while the corresponding ^-tier screw is located approximately diagonally opposite the respective intermediate web.

In the arrangement shown in Fig. 1·, the carrier 1 and the base body 3 are connected to each other via an intermediate web 4.

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l den. Instead, it is also possible to connect the support to the base body, e.g. using three adjusting screws or other connecting elements that replace the intermediate bar.

5 6 Protection claims 4 Figures

Claims (5)

&bull;&igr;« a ···»·■ &bull; · <· »it· 7 86 6 18 8 9 OE Protection claims 1. Adjustment device for an optical element, in particular for a reflector mirror of an optical resonator, which is arranged on a carrier which is adjustable relative to a base body having a reference surface or a reference element by means of at least one adjusting screw designed _in the manner of a differential screw, which has on its shaft two threaded areas lying one behind the other with different thread pitches, of which one threaded area is screwed into the carrier and the other threaded area is screwed into the base body, characterized in that a self-locking threaded insert (14 or 15) made of wire is provided between the threaded hole (18 or 10) in the carrier (1) and in the base body (3) and the two threaded areas (7 or 8) of the adjusting screw (6). 2. Adjusting device according to claim 1, characterized in that the threaded insert (14, 15) is shaped like a spiral spring and is self-locking by at least one straight wire part (16). 3. Adjustment device according to claim 1 or 2, characterized in that the threaded area (7) screwed into the carrier (1) has an M4 thread and the threaded area (8) screwed into the base body has an M5 thread and the threaded insert (14 or 15) is designed to correspond to these thread sizes. 4. Adjustment device according to one of claims 1 to 3, characterized in that the carrier (1) and the base body (3) are connected to one another via an elastic intermediate web (4). 5. Adjustment device according to claim 4, characterized in that the intermediate web (4) and the adjusting screw (6) are arranged in approximately diagonally opposite regions of the Il P · »I · I · .::..::.* .!..;:, ¹ S ₁ -JBOS 1 8 8 9 OE . &igr;&bgr; carrier (1) and the base body (3). % 6. Adjustment device according to claim 5, characterized in that the intermediate web (4) is designed and arranged in such a way that a connecting line from the central axis of the adjusting screw (6) to a surface of the intermediate web (4) facing the adjusting screw runs perpendicular to this surface