US20050183636A1

US20050183636A1 - Arrangement for tipping a table

Info

Publication number: US20050183636A1
Application number: US11/067,445
Authority: US
Inventors: Ingo Klemm; Jorg Meissner; Manfred Kresser; Matthias Jakob; Martin Ross-Messemer; Joachim Rulf
Original assignee: Carl Zeiss Jena GmbH
Current assignee: Jenoptik AG
Priority date: 2004-02-25
Filing date: 2005-02-25
Publication date: 2005-08-25
Also published as: CN1661414A; DE102004045256A1

Abstract

The invention relates to a tilting table array for micro-positioning objects, preferably for defined generation of oscillating movements of optical objects, such as for instance mirror elements in projection lens arrays, including a tilting table carrying the object and connected to at least one drive element as well as a tilting table housing that is coupled to the tilting table via an elastic connection. According to the invention, the tilting table, the tilting table housing and the elastic connection comprise one monolithic unit.

Description

FIELD OF THE INVENTION

The invention relates to a tilting table array for micro-positioning objects, preferably for defined generation of oscillating movements of optical objects, such as for instance mirror elements in projection lens arrays, including a tilting table carrying the object and connected to at least one drive element as well as a tilting table housing that is coupled to the tilting table via an elastic connection.

BACKGROUND OF THE INVENTION

DE 19700580 A1 describes a tilting table array for micro-positioning mirror elements in which a tilting movement of the mirror elements about two tilting axes is achieved by means of solid body joints attached to a base plate. Such arrays are very complicated in structure and therefore highly cost-intensive. Moreover, the serviceable life is relatively short due to wear phenomena that occur.
Tilting table arrays are also known in which an object carrier is connected to a tabletop via, for example, a rotating or tilting joint. The object carrier is tilted about the rotating joint using piezo elements that are arranged in the tabletop and in the object carrier at defined intervals from the rotating joint. Such an array is described in DE 19606913 C1, for example.
The disadvantage of all known arrays is that the complexity of assembling a device system is relatively high, because, in the majority of applications, it is necessary to affix and adjust the array in an additional housing.
This results in a large number of individual parts being needed for micro-positioning, which is associated with high complexity for making the adjustments and, therefore, significant costs, so that such arrays prove to be disadvantageous, particularly in mass production.
Based on the above, the object of the invention is to further develop a tilting table array for static or dynamic micro-positioning of objects such that virtually wear-free, highly accurate and cost-minimized positioning of an object is possible with relatively few individual elements.

SUMMARY OF THE INVENTION

This object is inventively achieved using a tilting table array of the type described initially in that the tilting table, the tilting table housing, and the elastic connection comprise one monolithic unit, wherein the elastic connection can be at least one bending element or at least one torsion element or at least a combination of both elements.
Because of the fact that the key functional elements of the tilting table array comprise one component, only a few individual elements are needed for micro-positioning an object.
In this connection, the monolithic unit can consist of either a metallic or a non-metallic material, and is usefully an injection molded part, a die-cast part or a combination of several shaping methods.
Dimensional variances in the array result solely from tool-related shaping tolerances, that generally are controllable with large numbers of units, however.
The relatively easily produced elastic connection between tilting table and housing allows for friction-free and play-free positioning of an object. This is especially important when, for example, optical components such as mirror elements must be dynamically moved with high frequencies. Moreover, highly precise positioning of sensors, such as for instance photodiodes, or sample manipulations are conceivable with the inventive tilting table array.
One advantageous variant consists in providing a base plate (locking lid), the tilting table array being positively or non-positively joined to the base plate. In this connection, it is also conceivable to attach the drive elements in the base plate, thereby joining them to the tilting table, so that there is also a positive or non-positive fit here.
For minimizing the individual elements and avoiding error sequences, however, it is advantageous to position and attach the drive elements in the tilting table housing.
Depending on the application, one or more drive elements can be provided that are arranged both symmetrically and asymmetrically on the tilting table adjacent to the elastic connection and that act thereon with the same or different force.
For generating counter-forces, it is useful to provide one or a plurality of spring elements between the tilting table and the tilting table housing or between the tilting table and the base plate.
In the case of tilting table arrays in which the position of a mirror element is dynamically modified in the micro-range with high frequencies (oscillating mirror), it is useful to provide piezo-actors as drive elements.
Piezo-actors possess the outstanding characteristic that short switching cycles with high power amplitudes are possible, even with small strokes (high accuracy of positioning).
Drive elements, such as drive elements that operate in accordance with the principle of magnetostriction (magnetic coils) and/or in accordance with the principle of differential transformation and/or in accordance with the principle of oscillating capacitors and/or in accordance with the principle of bending plates, are also conceivable. In addition, combinations with step motors and/or with hydraulic or pneumatic actors are also possible.
When piezo-actors are used, it proves to be useful to connect the drive elements to the tilting table via a sphere, because working a counter-contour against the actor permits defined positioning relative to the tilting table.
One variant of the inventive tilting table array consists in forming the elastic connection as a T-shaped joint. The rotation point of the joint can also be placed directly beneath the object using the structural design in terms of the height and depth as well as the position of the transverse beam. This causes a reduction in the moment of inertia of the tilting table, together with a frequently desired increase in the resonant frequency of the tilting system (rapid switching).
Modification of the torsional rigidity by varying the geometric dimensions of the T-joint also influences the resonant frequency of the tilting system, but also limits the amplitude if only a dynamic force is available. Because the rigidity of the elastic connection also depends decisively on the material of the monolithic unit and the injection molding process itself, it is possible to define this parameter using suitable tool design during production of the monolithic unit. Tool sets that can be used to determine the geometry of the T-joint can be easily exchanged during the production process.
One advantageous embodiment of the inventive tilting table array, especially when mirrors are to be positioned, consists in forming the object to be positioned, that is, the mirror, directly as a component of the monolithic unit, the surface of the tilting table comprising a metallic material being finely tooled such that it satisfies the requirements for an optical system. This is advantageous because even fewer individual elements are necessary, thereby minimizing the complexity of assembly.
Furthermore, when a specially produced object, such as a mirror element, is received on the tilting table, it is advantageous to provide an object receiver, wherein the connections between the object receiver and the tilting table and between the object receiver and the object should be designed as adhesive connections. The object receiver is usefully designed to be pot-shaped, its exterior base surface receiving the object and its interior wall provided for attaching to specially designed contours of the tilting table.
The advantage of this is that the object can initially be connected to the object receiver by means of an adhesive substance in a relatively simple manner. In a second assembly step, the object is then easily adjusted and affixed to the object receiver without distortion occurring in the object. In addition, the “object—object receiver” unit can be easily exchanged on the tilting table.
The tilting table movements, in connection with a compression spring that generates the counter-force, can lead to unpleasant vibrations, so that one advantageous further development of the inventive array consists in filling the interior space of the compression spring that is embodied as a spiral spring and that is limited by the tilting table and the tilting table housing or the tilting table and the base plate and/or the locking lid with an elastic shaping element.
The elastic shaping element usefully consists of a silicon rubber compound that completely fills the interior space of the spiral spring, thus allowing for stress-free attenuation of the compound elements without requiring additional rubber elements subject to tolerances.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the inventive tilting table array is described in greater detail using exemplary embodiments. The corresponding figures show:
FIG. 1 is a schematic view of the tilting table array with an elastic bending element,
FIG. 2 is a schematic view of the tilting table array with two elastic bending elements,
FIG. 3 is a top view of a tilting table array for an oscillating mirror with two elastic torsion elements,
FIG. 4 is a cross sectional view of the tilting table array according to FIG. 3 taken along section lines 4-4,
FIG. 5 is a cross sectional view of the tilting table array according to FIG. 3 taken along section lines 5-5, and
FIG. 6 depicts a torsion element in the form of a T-joint.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows, in schematic form, an embodiment of the inventive tilting table array, comprising a monolithic tilting table housing 1 with an integrated tilting table 2 and an integrated elastic bending joint 3. Via two drive elements 5 and 6 arranged symmetrically to the elastic bending element 3 in a base plate 4, forces are transmitted to the tilting table 2 so that the position of an object 7 affixed to the tilting table can be modified in accordance with the control of the drive elements 5 and 6.
FIG. 2 shows another exemplary embodiment of the design of a monolith, comprising a tilting table housing 8, a tilting table 9, as well as two elastic bending elements 10 and 11. This embodiment is easily produced by injection molding or die-casting, simply using open/shut tools without additional couplers, so that the cost of tools can be kept extremely low.
An inventive tilting table array for micro-positioning (oscillating movement) a mirror element 12 is shown in the exemplary embodiment depicted in FIGS. 3, 4 and 5, the same reference numbers identifying identical elements.
FIG. 3 shows the array in a top view from the side facing away from the mirror element 12 to be positioned (without a base plate and/or locking lid 13), comprising a tilting table housing 14 with an integrated tilting table 15. The tilting table 15 is connected to the tilting table housing 14 via two elastic torsion frames 16 and 17.
For the purpose of completing the positioning movement on the tilting table 15, that is, for generating the oscillating movement of the mirror element 12 (not shown in FIG. 3), a piezo-actor (piezo motor) 18 is located in the tilting table housing 14 that acts on one side of the tilting table 15 via a sphere 19, thereby displacing the tilting table. The counter-force to the force of the piezo-actor 18 is generated by a compression spring 20 affixed to the tilting table 15 and the locking lid 13, as can be seen in FIG. 4 (section 4-4 from FIG. 3).
An elastic shaping element 29 consisting of a silicone rubber mass is disposed in the interior space of the compression spring 20 formed as a spiral spring, limited by the tilting table 15 and a spring guide pin 28 molded to the locking lid 13.
Prior to the assembly of the locking lid 13, the silicone rubber mass is injected into the interior space of the spiral spring 20. During assembly of the locking lid 13, the spring guide pin 28 dips, without force, into the non-cross-linked silicone rubber mass that as a result precisely fills the interior space of the spiral spring 20. Then the silicone rubber mass vulcanizes in a tension-free manner. Tempering the assembled array accelerates cross-linking.
Both the piezo-actor 18 and the locking lid 13 are connected to the tilting table housing 14 via screw elements 21 and/or 22.
For the purpose of affixing the mirror element 12 to the tilting table 15, the surface of the tilting table 15 possesses two annular contours 23 and 24 that support a pot-shaped object receiver 25 carrying the mirror element 12.
The mirror element 12 is initially affixed to the pot-shaped object receiver 25 by means of tension-free adhesion. Then, as is more clearly evident from FIG. 5 (section 5-5 taken from FIG. 3), the pot-shaped object receiver 25 is placed onto the annular contours 23 and 24 and, following alignment in all degrees of freedom, connected to the tilting table 15 via an adhesive compound 26.
FIG. 6 shows a possible embodiment of the elastic connection between the tilting table 15 and the tilting table housing 14 in the form of a T-shaped joint 27 embodied as a torsion frame. The T-shaped joint 27, which, with regard to its torsional rigidity, depends on its geometric dimensions, such as depth T and length L, its position in the elastic connection, and the material, is torsionally soft without bending stiffness being significantly reduced. Low-frequency components of movement are blocked, thereby increasing the resonant frequency of the tilting system, which is decisive for rapid positioning procedures (switching procedures), especially in the case of optical elements. The adjustment of the T-shaped joint 27 already takes place during production of the monolithic unit in an injection molding process using specially manufactured variable tools. Mechanical retooling is unnecessary.

LIST OF REFERENCE NUMBERS

1, 8, 14 Tilting table housing
2, 9, 15 Tilting table
3,10, 11 Elastic bending element
4 Base plate
5, 6 Drive element
7 Object
12 Mirror element
13 Locking lid (base plate)
16, 17 Torsion frame
18 Piezo-actor (piezo motor)
19 Sphere
20 Compression spring
21, 22 Screw element
23, 24 Annular contour
25 Pot-shaped object receiver
26 Adhesive mass
27 T-shaped joint
28 Elastic element/silicone rubber mass
29 Spring guide pin

Claims

1. A tilting table array for micro-positioning an object, comprising a tilting table carrying the object and connected to at least one drive element and a tilting table housing that is coupled to the tilting table via an elastic connection, wherein the tilting table, the tilting table housing and the elastic connection comprise one monolithic unit.

2. The tilting table array according to claim 1, wherein the monolithic unit comprises a metallic material.

3. The tilting table array according to claim 1, wherein the monolithic unit comprises a non-metallic material.

4. The tilting table array according to claim 1, wherein the monolithic unit is an injection molded part, a diecast part or a combination of the foregoing.

5. The tilting table array according to claim 1, wherein the tilting table housing is connected, to a base plate or a locking lid serving the purpose of dust protection

6. The tilting table array according to claim 1, wherein the at least one drive element is affixed to the base plate or the locking lid and are positively or non-positively connected to the tilting table.

7. The tilting table array according to claim 1, wherein the drive element is attached in the tilting table housing.

8. The tilting table array according to claim 1, wherein the elastic connection comprises at least one bending element, at least one torsion element or a combination of the foregoing.

9. The tilting table array according to claim 1, wherein the elastic connection comprises a torsion element comprises a T-shaped joint modifiable in its geometric dimensions and in its position.

10. The tilting table array according to claim 9, wherein the T-shaped joint is adjustable by variable tools during the injection molding process.

11. The tilting table array according to claim 1, wherein the drive element is arranged such that its dynamic effect is directed adjacent to the elastic connection on the tilting table and wherein a counter-force is generated by a compression spring.

12. The tilting table array according to claim 11, wherein the interior space of the compression spring is filled with an elastic shaping element for the purpose of reducing vibration in the array.

13. The tilting table array according to claim 12, wherein the compression spring comprises a coil spring and the elastic shaping element comprises a silicone rubber mass that completely fills the interior space of the coil spring.

14. The tilting table array according to claim 1, comprising at least two drive elements that are arranged symmetrically or asymmetrically to the elastic connection and that act on the tilting table with the same or different force.

15. The tilting table array according to claim 14, in which the drive elements are arranged symmetrically.

16. The tilting table array according to claim 14, in which the drive elements act with unequal force.

17. The tilting table array according to claim 1, wherein the drive elements comprise piezo-actors.

18. The tilting table array according to claim 1 wherein the drive elements operate in accordance with the principle of magnetostriction, the principle of differential transformation, the principle of oscillating capacitors, the principle of bending plates, are step motors, hydraulic actors, pneumatic actors or a combination of the foregoing.

19. The tilting table array according to claim 1, characterized in that the drive element is connected to the tilting table via a sphere.

20. The tilting table array according to claim 1, wherein the object comprises an optical component.

21. The tilting table array according to claim 1, wherein the tilting table supports an object receiver, wherein the connections between the object receiver and the tilting table and between the object receiver and the object are formed adhesive bonds.

22. The tilting table array according to claim 21, wherein, the object receiver is pot-shaped and comprises an exterior base surface receiving the object and an interior wall for attaching to receiving contours of the tilting table for the purpose of attachment and assembly of the object to a reference plane.