WO2003001267A1

WO2003001267A1 - Mounting for an optical element

Info

Publication number: WO2003001267A1
Application number: PCT/NL2002/000418
Authority: WO
Inventors: Marcus Serwazi; Richard Spencer Batey; Nicolaas Grootenboer
Original assignee: Bihca Precision B.V.; Cvi Technical Optics Limited; Lambda Physik Ag
Priority date: 2001-06-22
Filing date: 2002-06-24
Publication date: 2003-01-03
Also published as: NL1018362C2

Abstract

A holder for a rotationally symmetrical optical element, comprising an annular housing provided with a passage in which the element can be received. In the direction of the passage, the housing has stops which lie opposite one another and between which the element is clamped. At least one of the stops interacts with a resilient element in order to exert a preloading force on the element.

Description

MOUNTING FOR AN OPTICAL ELEMENT

The invention relates to a holder for a rotationally symmetrical optical element, comprising an annular housing provided with a passage in which the element can be received.

Holders of this type with an optical element received therein are used, for example, in laser instruments. The optical element is usually secured in the holder by means of adhesive bonding. However, adhesive bonding of this type has drawbacks. For example, when a laser source is being used, the adhesive bond would cure under the influence of the laser light. This makes the service life of the join too short.

It is an object of the invention to provide a holder of the type described above which does not have these drawbacks. This object is achieved by the fact that the housing, in the direction of the passage, has stops which lie opposite one another and between which the element is clamped, and at least one of the stops interacts with a resilient element for exerting a preloading force on the element.

By means of the stops, the optical element can be secured in the housing under a predetermined clamping force. On the one hand, this allows the optical element to be held reliably in the correct position, while on the other hand the clamping force cannot exceed a specified level as a result of the action of the resilient element. This also makes it possible to prevent fluctuations in temperature from having an influence on the clamping.

The housing may have at least one spring member which extends in the circumferential direction and bears a stop, which spring element is resiliently deformable in at least the passage direction. Each spring member is supported by means of at least one spacer which extends in the passage direction.

The spring members may be designed in various ways; they are preferably in leaf form and have two ends which are each supported by means of associated spacers. There is a stop located centrally between the two ends of the spring member which is in leaf form. On account of the support of the spring members which are in leaf spring form, a design of this type gives a very stable position for the optical element. Moreover, the spring force can be adjusted relatively accurately by means of a leaf spring of this type.

There are preferably two series of spring members in leaf form, which series lie opposite one another in the direction of the passage and each extending in the circumferential direction of the housing. Each spring member in leaf form bears a stop centrally between its ends. The series may, for example, comprise three spring members in leaf form.

The optical element usually has a circular or cylindrical circumference. In that case, the housing may have a cylindrical internal surface and a cylindrical external surface, and the leaf springs may be correspondingly curved. Furthermore, the housing may comprise a central ring which bears spacers on either side.

Furthermore, the holder may be provided at both ends with covers with a central hole for passage of a light beam. For this purpose the spacers may each be extended by a cover support which extends beyond the spring members in leaf form, to which cover support two covers, which enclose the housing in the passage direction and are provided with an opening, are secured.

These covers overlap the stops at least partly in order to limit the deviations of these stops. In this way, it is possible to limit the risk of the spring members being overloaded as a result of excessive deviations thereof.

Each stop is formed by a hook member provided with a hole in which there is a securing bolt, and each resilient element bears a projection with an internally threaded hole into which the screw thread of the securing bolt is screwed.

Finally, the invention relates to an assembly comprising a holder as described above and an optical element which is received in the housing between the stops lying opposite one another, which stops are at a nominal distance from one another in the passage direction which is less than the corresponding dimension of the optical element, in such a manner that the stops hold the said optical element clamped under a preloading.

The invention will now be described in more detail with reference to an exemplary embodiment which is illustrated in the figures, in which:

Fig. 1 shows a cross section through the assembly comprising holder and optical element on section line I-I in Fig. 2.

Fig. 2 shows a side view of the assembly shown in Fig. 1.

Fig. 3 shows a cross section corresponding to that shown in Fig. 1 of the holder without the optical element.

Figs. 4 and 5 show a cross section and a side view of the housing of the holder.

Figs. 6 and 7 show a side view and a cross section of the left-hand cover of the holder.

Figs. 8 and 9 show a side view and cross section of the right-hand cover of the holder.

Figs. 10 and 11 show a front view and a cross section of a stop for the holder.

The assembly illustrated in Figs. 1 and 2 comprises a holder which is denoted overall by 1 and an optical element 2. As is also shown in Fig. 3, the holder 1 is provided with an annular housing 3 with a passage 4 in which, as illustrated in Fig. 1, the optical element 2 may be located.

The housing comprises a central ring 5 which has spacing members 6 in the direction of the passage. A spring member 7 which is in leaf form is formed between each pair of spacing members 6. In the exemplary embodiment illustrated, there are two series each having three springs 7 in leaf form and three spacing members 6.

Each spring member 7 in leaf form bears a projection 8, into which a bolt 9 is screwed in order to secure a hook member 10. This hook member 10 is illustrated in detail on a larger scale in Figs. 10 and 11. The hook member has a stop face 11 and a central hole 12 for receiving the bolt 9. Furthermore, the stop 10 in hook form has a stabilising protuberance 13 which rests against the outer side of the projection 8.

As illustrated in Fig. 3, in the nominal state the stops 11 lie at a certain distance from a left-hand cover 14 and a right-hand cover 15. These covers 14, 15 are illustrated in more details in Figs. 6 - 8. The covers 14, 15 are each secured to the extension pieces 17 of the spacers 6 by means of three bolts 16.

On account of this play, the hook members 10 can yield slightly in a resilient fashion. This fact is utilised when the optical element 2 is being fitted in the holder 1, as illustrated in Fig. 1. The dimension in the passage direction of the optical element 2 is slightly larger than the nominal distance between the stop faces 11 of the hook members 10, so that these members are pressed outwards slightly when the bolts 9 are tightened, with the spring members 7 in leaf form being elastically deformed. This ensures that the optical element 2 is clamped in a stable and temperature-independent manner.

Claims

1. Holder (1) for a rotationally symmetrical optical element (2), comprising an annular housing (3) provided with a passage in which the element can be received, characterized in that the housing, in the direction of the passage (4), has stops (10) which lie opposite one another and between which the element (2) is clamped, and at least one of the stops (10) interacts with a resilient element (7) for exerting a preloading force on the element (2).

2. Holder according to Claim 1, in which the housing (3) has at least one spring member (7), which extends in the circumferential direction and bears a stop (10), which spring member is resiliently deformable in at least the passage direction.

3. Holder according to Claim 2, in which each spring member (7) is supported by means of at least one spacer (6) which extends in the passage direction.

4. Holder according to Claim 3, in which each spring member (7) is in leaf form and has two ends which are each supported by means of associated spacers (6).

5. Holder according to Claim 4, in which there is a stop (10) between the two ends (6) of the spring member (7) which is in leaf form.

6. Holder according to Claim 5, in which at least two stops (10), which lie opposite one another in the direction of the passage, are each accommodated on a spring member (7) in leaf form, which spring members (7) are connected at their ends by spacers (6).

7. Holder according to Claim 6, in which two series of spring members (7) in leaf form are provided, which series lie opposite one another in the direction of the passage (4) and each extend in the circumferential direction of the housing (3), and each spring member (7) in leaf form bears a stop (10) centrally between its ends, which are each attached to a spacer (6).

8. Holder according to Claim 7, in which the housing (3) has a cylindrical internal surface and a cylindrical external surface, and the spring members (7) which are in leaf form have a correspondingly curved shape.

9. Holder according to Claim 8, in which each series comprises three spring members (7) in leaf form.

10. Holder according to Claim 7, 8 or 9, in which the housing (3) comprises a central ring (5) which bears spacers (6) on either side.

11. Holder according to Claim 10, in which the spacers (6) are each extended by a cover support (17) which extends beyond the spring members (7) in leaf form, to which cover supports (17) two covers (14, 15), which enclose the housing (3) in the passage direction and are provided with an opening (22), are secured.

12. Holder according to Claim 11, in which the covers (14, 15) at least partly overlap the stops (10) in order to limit deviations in the stops (10).

13. Holder according to one of the preceding claims, in which each stop is formed by a hook member (10) provided with a hole (12) in which there is a securing bolt (9), and each resilient element (6) bears a projection (8) with an internally threaded hole, into which the screw thread of the securing bolt (9) is screwed.

14. Assembly comprising a holder (1) according to one of the preceding claims and an optical element (2) which is received in the housing (3) between the stops (10) lying opposite one another, which stops (10) are at a nominal distance from one another in the passage direction which is less than the corresponding dimension of the optical element (2), in such a manner that the stops (10) hold the said optical element (2) clamped under a preloading.