JP6088614B2 - Optical device - Google Patents

Description

The present invention relates to an optical device. The optical device includes an optical element and a mount to which the optical element is fixed. The optical element is fixed to the mount via at least one compliant support portion (bearing), and the support portion is a first spring strut. And a spring strut arrangement having at least one second spring strut and a contact area where the optical element is fixed at the contact point, the first and second spring struts having a first end. To the contact area and to the outer edge of the mount via a second end remote from the contact area.

  The optical devices described above are generally known for their use.

An optical device of the type first mentioned can have relatively small optical elements, for example small lenses with a circular or polygonal outer periphery. Here, “small” optical elements, for example “small” lenses, refer to circular optical elements with a diameter of, for example, approximately 5 m.
It is in the range of about 30 mm from m.

In optical systems in which the optical device of the type mentioned at the beginning can be used, so-called doublets are sometimes used for aberration correction. Here, the doublet is, for example, 1 mm
A pair of lenses with an ultra-thin air gap of less than 1 and the air gap is typically 1
It is in the range of 0 μm to 100 μm. These doublet lenses have a great influence on the overall aberration of the optical system. The present invention is particularly suitable for an optical device having a doublet lens.

In addition to being high quality with respect to its material and surface, the optical element should not be able to induce as much as possible the damage of the correct position and surface shape by the mount, especially birefringence induced by stress. Need to avoid.

The demands for stable placement of optical elements, maintenance of surface shape, and avoidance of stress-induced birefringence are sometimes difficult to adjust. For stable placement, a stable connection between the optical element and the mount is required. However, the stable connection of the optical element to the mount causes a change in the surface shape and causes stress to generate birefringence. May be induced inside. These reciprocal effects are
This is further exacerbated when the optical element and / or mount heats during operation due to absorption. The optical element expands due to heating, which may cause stress in the optical element, and the optical characteristics of the optical element may be impaired.

A conventional optical device has a mount formed as a ring, for example, and the mount is formed with an annular offset in which the outer edge of the optical element is placed in the axial direction. A gap is left between the outer edge of the optical element and the mount body, and the gap is filled with an adhesive to fix the optical element to the mount. Due to environmental conditions (humidity in the atmosphere, short wavelength light) within the compound lens, the volume of the adhesive will fluctuate, and the balance of forces acting on the mount and lens will be affected accordingly, resulting in shape and / or Or the optical properties with respect to position will be impaired.

In addition to these conventional optical devices, there is also known an optical device in which the optical element is connected to the mount by a compliant support portion arranged around at least one, usually three, optical elements. In this case, each support portion includes a first spring strut and at least one
A spring strut arrangement having two second spring struts, the first spring strut and the at least one second spring strut extending to both sides of the contact area where the spring strut arrangement is coupled to the optical element; and Each other end is connected to an external area of the mount. Such a spring strut arrangement is sometimes referred to as a bilateral spring strut.

However, the configuration of the compliant support portion used with the bilateral spring strut cannot be easily used for, for example, a microlens in the above-described diameter range. For technical reasons related to production, the bilateral spring strut thickness is approximately 0.2
While such a bilateral spring strut arrangement is limited to the range of mm to 0.3 mm, the maximum length of the bilateral spring strut is constrained by two adjacent spring strut arrangements with respect to the other two supports, respectively. Depending on
Sufficient compliance cannot be achieved for the support. Deformation of the spring strut due to thermal expansion of the optical element can produce an undesirably high degree of stress in the spring strut arrangement, resulting in a high degree of compressive force corresponding to the optical element, inducing birefringence, The optical element may be deformed.

For small optical elements, it has also been proposed to replace the above-mentioned bilateral spring struts with simple unilateral spring struts, in which case only one spring strut extends from one side of the contact area and is mounted by the other end. It is fixedly connected to the main body. In such a configuration of spring struts, the aforementioned spatial problem no longer exists, ie a single spring strut can be longer than two spring struts of a bilateral spring strut, As a result, a lower stress is applied to the optical element as compared with the bilateral spring strut, and at the same time, a larger amount of deformation is ensured.

However, there is also a disadvantage in the construction of the spring strut with only the unilateral spring strut. The first disadvantage is that if the optical element has a heat-induced expansion in relation to the mount, the contact point between the contact area and the optical element is exposed to a bending moment, which causes the optical element to move into contact area. It may lead to peeling of the adhesive or solder that is connected to. As a result, the positional stability of the optical element is not guaranteed. A further disadvantage is that the unilateral spring strut is not rigid enough to avoid resonance under amplitude / vibration of the system in which the optical device is used. The resonance in the optical device causes a change in the position of the optical element that impairs the optical characteristics. Higher stiffness can be achieved by making the length of the spring strut shorter, but as described above, it involves a deterioration in the ratio of stress in the spring strut to the amount of deformation.

Therefore, fixing of the optical element to the mount of this kind by a spring strut arrangement having a unilateral spring strut is insufficient in view of the above-mentioned requirements.

The object of the invention is to provide an optical device of the kind mentioned at the outset, in which the optical element is fixed in a state as stable and as low as possible by means of a mount.

The object relates to the first mentioned optical device, i.e. first and second spring struts extending from the contact area on the same side of the contact area and separated from each other in the direction of compliance and substantially parallel to each other. This is achieved based on the invention.

The spring strut arrangement of the at least one support of the optical arrangement according to the invention comprises parallel spring struts formed by at least two parallel spring struts extending from one side of the contact area. In comparison with the spring strut arrangement of known optical devices, each having only one unilateral spring strut, the parallel spring struts of the optical device according to the present invention are free of adhesive or solder when the optical element expands. There is an advantage that no torque is generated at the contact point between the contact region and the optical element, causing separation at the contact point. This is because the parallel spring strut itself generates a moment in the contact area from the beginning that causes only a translation of the contact area that only results in rotation of the optical element without movement of the center of the optical element. .
The forces applied to the contact area by the first spring strut and the at least one second spring strut are all of equal magnitude and act in the opposite direction in the contact area. The distance in the direction of deformation between the two spring struts creates a torque that acts directly against the torque generated when the optical element expands.
As a result, no torque is generated at the contact point between the contact area and the optical element.

Further advantages of the parallel spring struts of the optical device according to the present invention include greater inherent stiffness compared to a spring strut arrangement with a single unilateral spring strut. The greater inherent stiffness of such a spring strut arrangement is better than a spring strut arrangement with only a smaller intrinsic stiffness,
The so-called positional stability of the optical element in the mount is ensured. Furthermore, the greater inherent stiffness of the support or support with parallel spring strut arrangement raises the natural frequency of the optical device to a higher frequency. This has the advantage that the amplitude or vibration in the optical system in which the optical device is installed cannot bring about a natural vibration in the optical device and improves the positional stability of the optical element.

As a result of the greater inherent stiffness of the parallel spring struts, the individual spring struts of the parallel spring struts can be made longer, which makes the ratio of stresses in the spring strut arrangement to the amount of deformation more advantageous. Become. That is, even if the radial expansion of the optical element causes a relatively large deflection in the spring strut arrangement, the stress on the spring strut arrangement causes stress in the optical element, particularly stress-induced birefringence. It will be smaller.

The spring struts are preferably formed as leaf springs, but can also be wires, slots in mounts, and the like.

In a further preferred configuration, the first and second spring struts are each
Between each first end and the second end, there is a curvature in a plane in which compliance occurs.

With respect to parallel spring struts, the configuration in which each spring strut is curved and extends parallel to each other is particularly advantageous with respect to eliminating bending moments in the region near the point where the optical element and the contact region contact.

From this point of view, it is more preferable that the spring strut has a concave shape as viewed from the optical element.

The configuration of the parallel spring struts that are concave when viewed from the optical element allows for better restoration of the spring strut configuration after radial deflection, such as when the optical device has finished operating and cooled again. There is an advantage.

In a further preferred embodiment, the spring struts are of substantially the same length.

A parallel spring strut configuration having spring struts that are of substantially the same length has the advantage that the overall spring characteristics of the parallel spring struts are more appropriately determined.

In a further preferred configuration, the at least one spring strut is such that its thickness and / or shape changes over its entire length, so that the stress is evenly distributed on the spring strut when the contact area is displaced. It is set as such.

Desirably, both spring struts in a parallel spring strut arrangement have a thickness and / or shape that varies over their entire length so that the stress is evenly distributed across the spring struts when there is displacement in the contact area.

The disadvantage of a spring strut having a uniform thickness, when deformed, generates a higher stress near the place where the spring strut is connected to the mount, for example compared to the middle of the length of the spring strut. Have As a result, the ratio of the deformation displacement amount and the rigidity is limited. In other words, it is necessary to reduce the rigidity in order to suppress the stress generated for a given deformation. However, the thickness over the entire length of the spring strut and / or
Or if the shape is designed to change, even if the deformation is maximum, an equal bending stress will occur over the entire length of the spring strut. In particular, this configuration can change the stress that secures the optical element and avoid plastic deformation of the parallel spring struts that can eliminate the optical element from optimal placement. In order to produce spring struts for parallel spring strut arrangements that vary in thickness and / or shape over their entire length, the mounts are produced in one piece and the spring struts from the mass of material to the desired thickness and / or Or it cuts out by wire electric discharge machining etc. so that it may have a change of shape.

In a further preferred configuration, the mount has three compliant supports each having a spring strut arrangement, and the two adjacent contact areas of each of the three contact areas of the three supports are preferably 120. They are spaced apart from each other around the optical element by an angle of °.

In this case, each of the three supports has a spring strut arrangement formed as a parallel spring strut. In this case, the three parallel spring struts are arranged to face in the same direction. That is, as seen from the direction around the optical element, the parallel spring struts of each support portion extend in the same direction from the respective contact areas. In this case, the thermal-induced expansion of the optical element or mount simply rotates the optical element around the optical axis, which does not involve movement of the center point of the optical element from the desired position.

As an alternative to the above configuration, the mount can have at least four compliant supports, each support having a spring strut arrangement, each of at least four contact areas of the at least four supports. The two adjacent contact areas are preferably spaced apart from one another around the optical element, preferably at 90 ° intervals.

Also in this configuration, the parallel spring strut arrangement of at least four supports is oriented in the same direction around the optical element. It is also possible to use more than three compliant supports within the scope of the present invention, and some or all of the supports can have a spring strut arrangement according to the present invention.

Preferably, in configurations with three or four compliant supports, these spring strut arrangements are formed with the same shape.

In a further preferred configuration, the optical device has a natural frequency higher than 1000 Hz, more preferably higher than 2000 Hz.

This property of the optical device according to the invention is that 1000 H in the optical system in which the optical device is installed.
The advantage is that the resonance of the optical device is not excited by vibrations or amplitudes of frequencies below z. High natural frequencies above 1000 Hz are in particular realized by the construction of the optical device according to the invention with parallel spring struts. This is due to the fact that parallel spring struts have a high degree of inherent rigidity while at the same time having a large compliance.

In a further preferred configuration, the optical device is provided with a second optical element and a second mount, the first optical element having a distance of less than 1 mm in the light propagation direction from the second optical element. The first mount has a first number of first supports for the first optical element;
The second mount has a second number of second supports for the second optical element, the first number being different from the second number.

This arrangement is particularly advantageous for mounting doublets, each individual lens being held by a mount according to the invention. A compliant support consisting of different numbers of parallel spring struts according to the present invention with respect to the two optical elements allows mutual excitation between the two mounts by causing different modes of motion and different natural frequencies. Is avoided.

The following configuration provides further aspects to the optical device according to the invention. When the optical element is connected to the contact area at the contact point using an adhesive, it is necessary to ensure that the adhesive is not destroyed by exposure to effective light. Short wavelength light (wavelength <400 nm,
In particular, ultraviolet light) destroys hydrocarbon-based adhesives by breaking hydrocarbon bonds. The failure of the adhesive is accompanied by the loss of contact between the optical element and the contact area of the mount, and the optical element can no longer be held in place. In addition, broken hydrocarbon bonds can emit gases and contaminate the surface of the optical element, which can impair transmission and imaging properties. Therefore, in the preferred embodiment of the present invention, the contact area and the contact point between the optical elements are protected from the effects of light.

For this purpose, in a first preferred configuration, the outer edge of the optical element is provided with a reflective and / or attractive coating in at least one region of at least one contact point.

This measure can advantageously prevent light from the optical element itself from hitting the contact point “from the inside”. Such “light from the inside” is generated by diffusion in the optical material of the optical element.

In a further preferred configuration, there is an aperture stop that blocks stray light / exogenous light in at least one contact area.

This means that the “external light” generated from other optical elements of the optical system, the mounts of the optical elements, and other mounts of other optical elements, ie stray light or extraneous light, strikes the contact point. Can be blocked.

  Preferably, the two configurations described above can be combined with each other.

In the last mentioned configuration, the aperture stop is placed very close to the at least one contact point, and the aperture stop is placed very close to the contact area on the optical element. It can also be formed as a coating.

In principle, it is advantageous to arrange the aperture stop at a small distance from the contact point in order to be able to block most of the stray light.

  Further advantages and features will become apparent from the following description and the accompanying drawings.

It goes without saying that the above-mentioned features and the features to be described below can be implemented not only in the combinations specified for each but also in other combinations without departing from the scope of the present invention.

Exemplary embodiments of the invention are represented in the drawings, the details of which will be described later with reference to the drawings.

It is a basic schematic diagram of a conventional optical device. It is the schematic when the optical apparatus in FIG. 1 has a small optical element. FIG. 6 is a schematic diagram of a further conventional optical device. It is a figure which shows the detail of the optical apparatus of FIG. 3 for demonstrating the influence of the thermal expansion of the optical element of the optical apparatus of FIG. 1 is a schematic view of an optical device according to a first embodiment of the present invention. 5A is a plan view, and 5B is a cross-sectional view of the optical device 5A taken along line VB-VB. It is the schematic which shows the detail of the optical apparatus of 5A and 5B for demonstrating the influence of the thermal expansion of the optical element of the optical apparatus of 5A and 5B. FIG. 6 is a schematic diagram of an optical device according to a further exemplary embodiment. 7A is a plan view, and 7B is a cross-sectional view of the optical device 7A taken along line VIIB-VIIB. FIG. 5 is a schematic diagram of an optical device representing a combination of optical devices according to 5A, 5B and 7A, 7B. 8A is a plan view, and 8B is a cross-sectional view of the optical device 8A taken along line VIIIB-VIIIB.

  1-4, an optical device according to the prior art is represented.

In FIG. 1, the optical device 200 is shown in a basic manner. The optical device 200 is
It has an optical element 202 that defines an optical axis 204 (the optical axis is perpendicular to the plane of the drawing). The optical device 200 also has a mount 206, which is schematically shown as a spatially fixed reference point in FIGS.

The optical element 202 is fixed to the mount 206 via three support portions 208a, 208b, and 208c. Each support portion bends in the radial direction in relation to the optical axis.

Supports 208a, 208b, and 208c each have a spring strut arrangement 210a.
210b and 210c. The three supports 208a, 208b, and 208c are evenly distributed on the outer edge of the optical element 202, i.e., are spaced 120 degrees from each other, and the spring strut arrangements 210a, 210b, and 210c are mutually connected. In the following, only the spring strut arrangement 210a will be described in detail.

The spring strut arrangement 210 a takes the form of a bilateral spring strut and has a first spring strut 212 and a second spring strut 214. Spring struts 212 and 214 extend from opposite sides of contact area 216 that fixedly couples spring strut arrangement 210a to optical element 202 and are secured to the body of mount 206 by respective ends 218 and 220 remote from the contact area. .

In FIG. 1, the solid line represents the normal state of the optical device 200 where the spring strut arrangements 210a, 210b and 210c are substantially slack. If this is the case, the optical element 20
2 is suddenly expanded radially in relation to the optical axis 204 (broken line), the spring strut arrangements 210a, 210b and 210c are correspondingly extended radially outward in relation to the optical axis 204. It is.

If the optical element as shown in FIG. 2 is small, the spring strut arrangements 210a, 210b and 210c are bilateral spring struts.
Individual spring struts cannot be of an appropriate length. In FIG. 2, the optical element 202 ′ has a much smaller diameter than the optical element 202 of FIG. For such a small optical element 202 ', the spring strut arrangements 210a', 210b 'and 210c' must cross each other. However, this is mechanically and technically
It cannot be realized from a production perspective.

Thus, as shown in FIG. 3, in the prior art, with respect to the optical device 200 ″, the spring strut arrangement 210 is used to secure the optical element 202 ″ to the mount 206 ″.
As shown for a ″, spring strut arrangements 210a ″, 210b ″ and 210c ″ each of the bilateral spring struts are intended to be fixedly connected to the mount 206 ″ via only one point 220 ″. Instead, spring strut arrangements 210a ", 21 having only unilateral spring struts 218"
It has been proposed to use 0b "and 210c".

As a result, mechanical interference of the spring strut arrangements 210a ", 210b" and 210c "is avoided even when the optical element 202" is small. Also, 1 to mount 206 "
Since there is only one connection, spring strut arrangements 210a ", 210b" and 21
0c "has a softer or lower spring stiffness, in other words, spring strut arrays 210a", 210b "and 210c" have a lower intrinsic stiffness, thereby giving the optical arrangement 200 "a lower natural frequency.

Similar to that shown in FIG. 4, the configuration according to FIG. 3 also has the optical element 202 ″ (dashed line portion in FIG. 3).
As the bending moment is applied to the contact region 216 ", more specifically the arrow 224".
Acting at the contact point 222 ", to which the optical element indicated by
It has the disadvantage of generating a stress distribution as indicated by the arrow 226 "at the contact point 222", which generates a tensile stress at 22 ". For example, debonding of the adhesive or solder that joins the optical element 202 "may occur, resulting in no longer guaranteeing a stable placement of the optical element 202" on the mount 206 ".

The optical device according to the invention is described below with reference to FIGS. 5-8, in which the disadvantages of the prior art described above are avoided.

FIGS. 5A and 5B show an optical device 10 having an optical element 12 defined by an optical axis 14 and also having a mount 16.

In the exemplary embodiment shown, the optical element 12 is a plano-convex lens with a circular outer periphery. Specifically, the optical element 12 is a small lens having a diameter of several millimeters. The optical element 12 may be a cylindrical lens or the like that does not have rotational symmetry, for example. Accordingly, it should be understood that the presence of the optical axis 14 is exemplary.

The mount 16 preferably has a metal body and is manufactured as a whole and has an annular outer periphery 18 and a base 20.

Optical element 12 is mounted on mount 16 with three compliant supports 22a, 22b and 2;
It is fixed via 2c. In the exemplary embodiment shown, compliance is radial with respect to the optical axis 14. Since the support portions 22a to 22c are formed in the same shape, only the support portion 22a will be further described below as an example. The following description applies to the support portions 22b and 22c as well.

The support portion 22a includes a first spring strut 26 and a second spring strut 2
8 and a spring strut arrangement 24 having a contact area 30. The optical element 12 is fixed to the contact area 30 at the contact point 32 by adhesion or soldering. The contact area 30 takes the form of a contact brace.

The first end 34 of the first spring strut 26 and the second spring strut 2
The first end 36 of the eight is connected to the contact area 30 as one piece. In this case, the ends 34 and 36 are arranged approximately in parallel or opposite to each other in the longitudinal direction of the spring struts 26 and 28.

  The spring struts 26 and 28 are formed as leaf springs.

Both spring struts 26 and 28 extend to one side of the contact area 30. The second end 38 of the contact region first spring strut 26 and the second end 40 of the second spring strut 28, which are remote from the contact region, are similarly integral and mounted on the mount 16.
The base 20 is connected to an outer region as viewed from the optical element 12. Ends 38 and 40 are also arranged facing each other.

The first spring strut 26 and the second spring strut 28 are separated from each other in the direction of their compliance, this direction being in a plane perpendicular to the optical axis 14 (ie the plane of the drawing according to FIG. 5A). ), The separation distance is small compared to the length of the leaf springs 26 and 28. The first spring strut 26 and the second spring strut 28 then extend substantially parallel to each other between the respective first ends 34 and 36 and second ends 38 and 40, resulting in Form parallel spring struts. “Substantially parallel” includes the case where the spring struts 26 and 28 have a small angle of less than 10 ° relative to each other.

Between each first end 34 or 36 and each second end 38 or 40,
The first spring strut 26 and the second spring strut 28 are curved in a plane where compliance occurs, and the curvature of these two spring struts is concave when viewed from the optical element 12. Further, the lengths of the first spring strut and the second spring strut are substantially the same, and because of the curvature, the first spring strut 26 is more than the second spring strut 28 as an “outer” spring strut. Slightly long.

Although the leaf spring arrangement 24 shown in the exemplary embodiment has two spring struts, a greater number of spring struts, for example three or four spring struts, are provided in the leaf spring arrangement 24. The increase in the number of spring struts can lead to an increase in the inherent stiffness of the spring strut arrangement 24.

However, the spring strut arrangement 24 with two spring struts 26 and 28 already has a large inherent rigidity because of its construction, and the optical device 10 as a whole is 10.
In the exemplary embodiment shown having a natural frequency of 00 Hz or higher, 2
It exceeds 000 Hz.

As already mentioned above, the mount 16 of the optical device 10 has a total of three compliant supports 22a, 22b and 22c, which are likewise formed by parallel spring struts, respectively. Spring strut arrangement
As shown in FIG. 5A, each is the same as the spring strut arrangement 24 except in position. The individual spring strut arrangements of the supports 22a, 22b and 22c are oriented in the same direction around the optical element 12, and the contact areas of the three parallel spring strut arrangements are in pairs and spaced 120 ° around the optical element 12 Is arranged in.

The contact area 30 (the same can be said for the two contact areas of the supports 22b and 22c) has a stop 44, which is provided in the continuation of the contact area 30 and of the spring strut arrangement 24. In order to limit the travel path, it acts with a receiving portion 46 on the body of the mount 16. This prevents overstretching of the spring strut arrangement 24, which can cause other undefined stressing conditions on the spring strut arrangement 24 due to irreversible deformation when the optical element 12 is incorporated. To play a role.

The effect of the expansion of the optical element 12 on the connection at the contact point 32 of the contact area 30 to the optical element 12 will be described below with schematic views 6a) to c).

FIG. 6a) shows a schematic view of the spring strut arrangement 24 of FIG. 5A in a relaxed state. As the optical element 12 (not shown in FIG. 6) expands in the radial direction, the optical element 12 applies a force F to the contact region 30, thereby exaggeratingly shown in FIG. A deflection of the parallel spring struts 26 and 28 is provided. Unlike the unilateral spring strut of FIG. 4, a bending at the contact point 32 between the contact area 30 and the optical element 12 may lead to peeling of adhesive or solder between the contact area 30 and the optical element 12. No moment is generated. This effect is brought about by the spring strut arrangement 24 being configured as a parallel spring strut. This, while the first spring strut 26 by deformation is added to the contact region 30 a force _{F 1} by arrow 50 in FIG. 6c), the force the second spring strut 28 by arrow 52 in FIG. 6c) _{F 2} Because the forces F ₁ and F ₂ are equal in magnitude but opposite in direction of action. The distance in the direction of compliance between the two spring struts 26 and 28 produces a torque M according to the arrow 54 in FIG. 6c), whereby the optical element 1
The force F exerted by 2 is canceled out. As a result, no combined torque is generated at the contact point 32 between the contact region 30 and the optical element 12. In other words, spring strut 2
The parallel spring struts with 6 and 28 themselves generate a moment that counteracts the moment exerted by the optical element 12 in the contact area 30, which leads to the effect that the contact area 30 only translates. When thermal expansion occurs in the optical element 12 or expansion of the support portions 22a, 22b and 22c of the spring strut arrangement occurs, at the contact point between the optical element 12 and the contact area of the support portions 22a, 22b and 22c. Only a slight rotation about the optical axis of the optical element 12 is generated without a bending moment that causes peeling of the adhesive or solder.

The spring struts 24 of the optical device 10 according to FIGS. 5A and 5B (as well as the spring struts of the supports 22b and 22c) are preferably integrally formed with the other parts of the body of the mount 16. FIG. Spring strut arrangement 24 and supports 22b and 22c
The spring strut arrangement is preferably formed from the base of the mount 16 by, for example, wire electric discharge machining. Accordingly, the mount 16 as a whole is preferably integral. Accordingly, the spring strut arrangement 24 and the support portions 22b and 22 are provided.
The spring strut arrangement of c is created by the material extraction portion 56 of the base 20, and an additional material extraction portion in the form of an elongated hole in FIG.

The integral formation of the mount 16 including the spring strut arrangement 24 and the spring strut arrangement of the support portions 22b and 22c ensures that even if there is a radial displacement of the contact region 30, the stress is uniformly distributed in the spring struts 26 and 28. The spring struts 26 and 28 have a thickness and / or shape that varies over the entire length between the first end 34 and 36 and the second end 38 and 40 so that the effect of the distribution can be obtained. There is an advantage that can be made.

This is because the spring strut having a uniform thickness is deformed by the second end 38.
And 40, ie the part where the spring strut is connected to the body of the mount 16 has the disadvantage that it is subjected to a higher stress than, for example, the middle of the total length of the spring struts 26 and 28. As a result, the ratio between the deformation displacement amount and the rigidity is limited, that is, in order to suppress the stress generated for a given deformation, it is necessary to reduce the rigidity. When the load is applied only once in a short time, for example, the optical element 12 is mounted 1
In the case of being incorporated into 6, the Rp _0.2 limit value is used as an allowable stress. The Rp _x limit value is understood to mean the stress at which the elongation that remains permanently even when there is no load is x%. For operating situations that last longer or occur more frequently, the maximum allowable stress is further limited to the Rp _0.05 limit. This avoids plastic deformation of the spring struts 26 and 28 resulting from relaxation, and avoids stress changes caused by a theoretically new unstressed state that may move the center point of the optical element 12. The Spring struts cut and incorporated from steel sheets can only be produced cost-effectively with a uniform thickness. Therefore, within the scope of the present invention,
In order to freely determine the thickness and / or shape of the spring struts 26 and 28 over their entire length, the mount 16 is preferably produced integrally by, for example, wire electric discharge machining. By means of finite element analysis, the amount of change in the thickness and / or shape of the spring struts 26 and 28 is optimized so that the same stress acts on the entire length of the spring struts 26 and 28 under the maximum displacement. .

In the exemplary embodiment shown, the area of the second end 38 of the first spring strut 26 is approximately 25% more thick than the area of the first end 34 (thickness is the optical axis 14).
In a plane orthogonal to the

Some of the stresses generated by the different expansions of the optical element 12 and the mount 16 can be prevented by using a material that matches well with the optical element 12 with respect to the coefficient of thermal expansion. When quartz having a very low expansion coefficient (0.5 ppm) is used for the optical element 12, an invar which is an iron-nickel alloy having an expansion coefficient of approximately 1.5 to 2.5 ppm is particularly suitable for the mount 16. It is. The optical element 12 is CaF ₂ (expansion coefficient is 19 pp
In the case of m), aluminum (expansion coefficient of 22 ppm) is particularly suitable as the material of the mount 16. When determining the optimal material of the mount from the viewpoint of the coefficient of thermal expansion, it is necessary to pay attention to the temperature change occurring in the mount 16 as a whole. This depends on the energy absorbed by the optical element 12 and the mount 16. Special attention must be paid to the contact point 32 between the optical element 12 and the contact area 30 and to the mount 16, for example, the adhesive or solder must not already be destroyed by heat-induced stress.

7A and 7B, a further exemplary embodiment of the optical device 60 is shown, the details of the optical device 60 being the same, similar or similar to that of the optical device 10, with the corresponding reference number being 5.
Referenced by a number with 0 added.

The optical device 60 includes an optical element 62, and the optical element 62 is formed as an uneven lens. The optical element 62 is a small lens, but is larger than the optical element 12 of the optical device 10 and has a diameter of about 15 mm to 20 mm, for example. Again, the optical element 62 defines an optical axis 64.

The optical device 60 also has a mount 66 that has an outer peripheral edge 68 and a base 70.

The optical element 62 is provided on the mount 66 by at least four, here exactly four, compliant supports 72a, 72b, 72c and 72d. Support part 7
Each of 2a, 72b, 72c and 72d has a spring strut arrangement, and the spring strut arrangements of these support portions 72a, 72b, 72c and 72d are formed in the same shape as each other. Only one spring strut arrangement 74 of 72a will be described.

The spring strut arrangement 74 has a first spring strut 76 and a second spring strut 78, both of which are parallel spring struts as described with respect to the optical device 10 referring to the spring struts 26 and 28. Form. The spring strut arrangement 74 also has a contact area 80, which is connected to the optical element 62 via a contact point 82, for example by an adhesive or solder.

For the configuration of the spring strut arrangement 74, reference may be made to the entire description of the spring strut arrangement 24 of the optical device 10 of FIGS. 5A and 5B.

As a difference from the optical device 10, the optical device 60 has a total of four support portions 72 a to 72 d, and correspondingly, the optical device 60 has four spring strut arrays such as a spring strut array 74. The support struts 72a to 72d have two spring strut arrangements arranged at 90 ° intervals around the optical element 60, and the remaining spring struts are also spring struts 76 and 7 of the spring strut arrangement 74.
As shown in FIG. 8, the optical element 62 is oriented in a uniform direction between the support parts.

The mount 66 is made integrally as a whole, including the spring struts of the support struts 72a to 72d.

FIGS. 8A and 8B show a further optical device 90 comprising an assembly combining the optical device 10 and the optical device 60.

As shown in FIG. 8B, the optical device 60 is incorporated in the optical device 10 so that the distance between the optical element 12 and the optical element 62 is less than 1 mm in the light propagation direction. That is, only a minimal air gap exists in the direction of the optical axis 94 between the optical element 12 and the optical element 62 in the exemplary embodiment shown.

In this case, the optical element 12 and the optical element 62 constitute a doublet used in the optical system for aberration correction.

When assembling the optical devices 10 and 60 in the optical axis direction, the mount 16 mounts the optical element 12 by three compliant supports 22a, 22b and 22c, and the mount 66 causes the optical element 62 to move around the optical axis 94. Due to the mounting by four compliant supports 72a, 72b, 72c and 72d offset from each other, the following advantages are obtained. One advantage is that different modes of motion and natural frequencies occur in the optical devices 10 and 60, and as a result, mutual excitation between the optical device 10 and the optical device 60 that causes natural vibrations is avoided.

According to a further aspect of the invention, the contact areas 30 and 80, whether the light is effective light used during operation of the optical device 10, 60 or 90 or stray light or extraneous light.
Means are taken with respect to the optical devices 10, 60 and 90 to protect the contact points 32 and / or 82, which respectively connect to the optical element 12 or 62, from the effects of light. The reason is
This is because when the bonding is performed in the contact region 32 or 82, particularly when the adhesive is based on hydrocarbons, such light can cause the adhesive to break.

The first means applies at least a contact point 32 or 8 to the optical element 62 and / or the optical element 12.
Applying a reflective and / or aspiration coating for the effective light used or the stray light or extraneous light being generated at the outer edge 96 or 98 of area 2 (see FIG. 8B) It is. This measure prevents "inner light", i.e. light in the optical element 12 or 62 radially diffused towards the outer edge 96 or 98, from reaching the contact point 32 or 82.

The second means is for the optical device 10, 60 or 90, the optical device 10 and the optical device 90.
An aperture stop as shown in FIG. Such an aperture stop 100 is shown in FIGS. 5A and 5B and 8B. When viewed in the direction of light propagation, the aperture stop 100
Is placed in close proximity to the contact point 32 of the optical element 12 and the contact area 30 is placed in front of the optical element 12 so that extraneous light or stray light is applied to the adhesive at the contact point 32. Is effectively prevented from reaching.

In the case of the optical element 62, reducing the exposure of extraneous light or stray light to the contact point 82 is already ensured by having the region 102 extended radially. The radially extended region 102 extends outside the optically used region 104 of the optical element 62, and by this means, the contact point 82 has already been considerably displaced radially outward, so that the extraneous light Alternatively, stray light does not hit the contact point 82 or hits it only slightly.

Needless to say, the above-mentioned means for protecting the contact points 32 and 82 can be combined with each other.

DESCRIPTION OF SYMBOLS 10 Optical apparatus 24 Spring strut arrangement 60 Optical apparatus 90 Optical apparatus 200 Optical apparatus 200 'Optical apparatus 200 "Optical apparatus 210c" Spring strut arrangement

Claims (13)

An optical element (12; 62);
A mount (16; 66) to which the optical element (12; 62) is fixed, wherein the mount (16; 66) material matches the optical element (12; 62) with respect to the coefficient of thermal expansion ( 16; 66),
The optical element (12; 62) is fixed to the mount (16; 66) via at least one elastically deformable support (22a-c; 72a-d),
The support portion (22a-c; 72a-d) includes a first spring strut (26; 76), at least one second spring strut (28; 78), and the optical element (12; 62). A spring strut arrangement (24; 74) having a contact area (30; 80) fixed at the contact point (32; 82);
The first and second spring struts (26, 28; 76, 78) reach the contact area (30; 80) via the first end (34, 36; 84, 86) and the contact. An optical device coupled respectively to the outer edge (42; 92) of the mount via a second end (38, 40; 88, 90) remote from the area;
The first and second spring struts (26, 28; 76, 78) extend from the contact area (30; 80) on the same side of the contact area (30; 80) and are in the direction of elastic deformation relative to each other. separated, Ri substantially parallel der each other,
The optical device according to claim 1, wherein the contact region includes a stopper that acts on a receiving portion provided on the mount and restricts a movement path of the spring strut arrangement .   2. The optical device according to claim 1, wherein the first and second spring struts (26, 28; 76, 78) are formed as leaf springs. The first and second spring struts (26, 28; 76, 78) are respectively connected to the first end (34, 36; 84, 86) and the second end (38, 40; 88, 90), the optical device according to claim 1, wherein the optical device has a curvature in a plane in which elastic deformation occurs.   4. The optical device according to claim 3, wherein the curvature of the spring struts (26, 28; 76, 78) is concave when viewed from the optical element.   The optical device according to any one of claims 1 to 4, wherein the spring struts (26, 28; 76, 78) have substantially the same length. When the contact area (30; 80) is displaced in the direction of elastic deformation of the spring strut (26, 28; 76, 78), the stress is uniformly distributed to the spring strut (26, 28; 76, 78). Thus, at least one of the spring struts (26, 28; 76, 78) varies in thickness and / or shape over its entire length. The optical device described. The mount (16) has three elastically deformable supports (22a-c) each having a spring strut arrangement (24), and three contact areas (30) of the three supports (22a-c). 2) each of the two adjacent contact areas are preferably spaced apart from each other around the optical element (12; 62), preferably at 120 ° intervals. The optical device according to any one of the above. The mount (66) has at least four elastically deformable supports (72a-d) each having the spring strut arrangement (74), and at least the four of the at least four supports (22a-d). The two adjacent contact areas of each of the two contact areas (80) are preferably spaced apart from one another around the optical element (12; 62), preferably at 90 ° intervals. The optical device according to any one of claims 1 to 6.   9. The optical device according to claim 1, wherein the optical device has a natural frequency higher than 1000 Hz. A second optical element (62) and a second mount (66);
The first optical element (12) has a distance of less than 1 mm in the light propagation direction from the second optical element (62);
The first mount (66) has a first number of the first supports (22a-c) for the first optical element (12);
The second mount (66) has a second number of the second supports (72a-d) for the second optical element (62),
The optical device according to any one of claims 1 to 9, wherein the first number is different from the second number.   The outer edge (96; 98) of the optical element (12; 62) is provided with a reflective and / or suction coating at least in the region of the at least one contact point (32; 82). The optical device according to claim 1, wherein the optical device is an optical device.   The optical device according to any one of the preceding claims, further comprising an aperture stop (100) for blocking the at least one contact point (32) from stray light / exogenous light. 13. Optical device according to claim 12, characterized in that the aperture stop (100) is arranged very close to the at least one contact point (32).

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