JP2006221180A - Device for setting divergence and/or convergence of light beam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for setting the divergence and/or convergence of a light beam with which the divergence and/or convergence can be set quickly. <P>SOLUTION: The device for setting the divergence and/or convergence of a light beam (1), particularly in a scanning microscope, includes at least one optical component (2) that sets the divergence and/or convergence of the light beam (1), and includes a positioning device (3) for the component (2). The positioning device (3)includes at least one piezoelectric element (4). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an apparatus for adjusting the divergence and / or convergence of a light beam, in particular with a microscope such as a scanning microscope, the adjustment apparatus comprising at least one for adjusting the divergence and / or convergence of the light beam. It relates to a type having one optical component and a positioning device for this component.

  Adjustment devices of the type mentioned at the beginning are in fact known and exist in different configurations. For example, mechanical motors that adjust the position of the optical components are used to adjust the divergence and / or convergence of the light beam within the microscope.

  A problem with known devices for adjusting the divergence and / or convergence of a light beam is that mechanically powered devices have an apparently too slow adjustment speed for many applications. In other words, the optical component cannot be positioned as quickly as required for each application. Furthermore, undesired vibrations frequently occur in known devices during the component positioning process. In this case, exploration or inspection is often not possible with vibration sensitive samples.

  It is therefore an object of the present invention to improve an apparatus for adjusting the divergence and / or convergence of a light beam of the type mentioned at the outset, so that a rapid divergence and / or convergence adjustment is possible. is there.

  According to the invention, the object is solved by an apparatus for adjusting the divergence and / or convergence of a light beam, comprising an arrangement of the characterizing part of claim 1 in an adjusting device of the type mentioned at the outset. That is, the adjusting device is configured such that the positioning device has at least one piezoelectric element.

  According to the present invention, a piezoelectric element can be used advantageously to position the optical component. This type of piezoelectric element makes it possible to adjust the optical component at high speed with little vibration. By applying an appropriate voltage, the optical component coupled to the piezoelectric element can be easily positioned. By properly positioning the (optical) components, the imaging characteristics of the system can be changed.

  Therefore, the apparatus for adjusting the divergence and / or convergence of the light beam according to the present invention provides an adjustment device capable of quickly adjusting the divergence and / or convergence.

  In a specific configuration of the adjusting device, at least one piezoelectric element can have a substantially tubular region. Application of a voltage changes the length of the tubular region, thereby positioning the (optical) component. At this time, the light beam is guided through the central hole of the tubular region.

  In another specific configuration, at least one optical component can each be arranged at at least one end (preferably both ends) of the tubular region. Here, a configuration in which at least one optical component is arranged at both ends of the tubular region is particularly advantageous. When a voltage is applied to the piezoelectric element or the tubular region, the distance between the optical components arranged at both ends changes mutually. This changes the imaging characteristics of the entire optical system in which the adjusting device is used. More precisely, the axial length of the tubular region can be extended and / or shortened (increased or decreased) by applying a voltage.

  In another embodiment, for example, two piezoelectric elements comprising tubular regions can be used, with at least one optical component being arranged in each tubular region. The two piezoelectric elements can advantageously be controlled by the same drive electronics. Therefore, the piezoelectric elements are connected in parallel in a pseudo (electrical) manner. In either case, the mutual spacing between the optical components can be changed by applying an appropriate voltage.

  The adjustment device can advantageously be configured such that the focal points of the plurality of optical components coincide with each other without application of voltage (i.e. the focal point can be configured at each predetermined reference position). In this case, the light that is collimated at one end (collimated) and incident on the tubular region is collimated again at the other end and leaves. To adjust the focused or diverged light beam, the tubular region is extended or shortened by applying a control voltage. In this type of situation, the focal points of the optical component (s) no longer coincide. Therefore, the light beam passes through the tubular region and is adjusted for convergence or divergence.

  Alternatively, the arrangement of the optical components can be selected such that the focal points of the optical components do not coincide with no voltage.

  In a particularly simple configuration of this device, the optical components arranged on one and the other of the tubular regions have the same focal length. In the simplest configuration, the optical components disposed at one and the other end of the tubular region are similarly configured.

  In still other configurations, the optical components disposed on one and the other of the tubular regions have different focal lengths. In this case, the adjusting device can be configured such that the light beam diverges (expands) when passing through the tubular region. As a result, a beam expander having an adjustable divergence can be realized.

  In a particularly simple construction, at least one optical component can be a lens or a lens system. The lens here is preferably a positive lens. As a configuration, at least one optical component may be an achromatic lens.

  In the device according to the invention, the two optical components can be used in a piezoelectric element configured as a tube piece (Roehrchen) of a predetermined length or in the tubular region of the piezoelectric element. This achieves a much higher adjustment speed compared to conventional systems. This is because the inertia of the system is much smaller when the optical action is the same than when the optical components are individually controlled. This is important, for example, for adjusting the divergence of the light beam in a confocal laser scanning microscope in synchronism with the scanning motion of the laser beam. This allows, for example, image field distortion of the microscope objective to be compensated by a z-scan of the laser focus matched (adapted) thereto. This z-scan is formed by divergence adjustment. Since this adjusting device can be configured to be completely symmetrical, it is minimized that each higher system is vibrationally excited.

  With the adjusting device of the present invention, a z-scan (scan in the optical axis direction) of the laser beam focus can be executed with a microscope. Alternatively or additionally, the adjustment device can perform image field distortion correction in the microscope. Furthermore, by way of example or in addition, this adjustment device makes it possible to carry out correction of chromatic aberrations or field distortions for individual colors in the microscope.

Basically, the resonance frequency f of the piezoelectric tube piece satisfies the following proportional relationship:
f to √ (stiffness / motion mass) [f to √ (Steifigkeit / bewegte Masse)]
When the piezoelectric tube piece is halved, the rigidity is doubled. Accordingly, the resonance frequency increases by a factor of 1.4.

  The resonance frequency is further increased by reducing the mass of the piezoelectric tube piece in accordance with the relative size between the mass of the “load” attached to the piezoelectric tube piece and the mass of the piezoelectric tube piece. If the piezoelectric tube piece has no external load, another coefficient √2 is obtained, and in a limit example where the intrinsic mass of the piezoelectric tube piece is negligible with respect to the external load, the coefficient is 1. That is, it has no effect.

Various means exist to advantageously construct and improve the technical idea of the present invention. Reference is made on the one hand to the dependent claims and on the other hand to the following description of advantageous embodiments of the invention based on the drawings. In connection with the description of advantageous embodiments of the inventive idea on the basis of the drawings, generally advantageous configurations and improvements are also described.
It should be noted that the reference numerals attached to the claims of the claims are only for the purpose of helping understanding, and are not intended to be limited to the illustrated embodiments.

Form 1. (Claim 1: supra)
Form 2. At least one piezoelectric element is characterized by having a substantially tubular region.
Form 3. It is characterized in that at least one optical component is arranged at least at one end and preferably at both ends of the tubular region.
Form 4. The axial length of the tubular region is characterized in that the voltage is extended and / or shortened by application.
Form 5. The focal point of each optical component coincides with the reference position in a no-voltage state (the focal points of the plurality of optical components coincide with each other).
Form 6. The focal point of each optical component is characterized in that it does not coincide with the reference position in the absence of voltage.
Form 7. Each optical component disposed on one and the other of the tubular regions has the same focal length.
Form 8. The optical components arranged in one and the other of the tubular regions are configured in the same manner as each other.
Form 9 The optical components arranged in one and the other of the tubular regions have different focal lengths.
Form 10 At least one optical component is characterized in that it is a lens, preferably a positive lens.
Form 11 At least one optical component is an achromatic lens.
Form 12 The adjustment device performs scanning in the optical axis direction of the focal point of the light beam, that is, the z direction, in the microscope.
Form 13 Image field distortion is corrected in the microscope by the adjusting device.
Form 14 The adjustment device performs correction of chromatic aberration or field distortion for each color in the microscope.
Form 15. A microscope comprising the adjustment device according to any one of Embodiments 1 to 14.
Form 16. A scanning microscope comprising the adjusting device according to any one of Embodiments 1 to 14.

  FIG. 1 shows a schematic side view of an embodiment of the device according to the invention for adjusting the divergence and / or convergence of a light beam 1. This device can be used inter alia in confocal laser scanning microscopes. This device has two optical components in the form of a positive lens system similarly configured. The lens adjusts the divergence and / or convergence of the light beam. This device further comprises a positioning device 3 for the lens. From the viewpoint of adjusting the divergence and / or convergence particularly fast, the positioning device 3 has a piezoelectric element 4. Thereby, not only can divergence and / or convergence adjustment be performed at high speed, but also can be performed with little vibration. This is particularly advantageous for microscopic applications.

  The piezoelectric element 4 has a substantially tubular region 5, and the light beam 1 passes through this tubular region (its central hole space). In other words, a piezoelectric tube piece (or small tube Roehrchen) is realized. The optical component 2 is in the form of a lens and is arranged at both ends of the tubular region 5. By applying a voltage, the axial direction (z-axis direction) length of the tubular region 5 can be extended and / or shortened.

  In the embodiment shown in FIG. 1, no voltage is applied. Accordingly, the collimated light beam 1 incident on the piezoelectric tube piece (to a parallel light beam) is collimated again and emitted from the piezoelectric tube piece.

  FIGS. 2 and 3 respectively show the case where a different voltage is applied to the tubular region 5 in the embodiment of FIG. That is, the shortening of the tubular region 5 or the piezoelectric tube piece is caused in FIG. 2, and the extension is caused in FIG. Accordingly, in the situation of FIG. 2, a diverged light beam 6 is formed, and in the situation of FIG. 3, a converged light beam 7 is formed.

  In the absence of voltage, the focal points of the two optical components 2 or the positive lens system in FIG. In FIG. 1, two optical components 2 in the form of a positive lens system have the same focal length.

  With the adjusting device of the present invention, it is possible to quickly execute a cyst in the optical axis direction of the focus of the laser beam 1, that is, scanning (z-direction scanning) with a microscope. Furthermore, correction of image field distortion and / or chromatic aberration (Farblaengsfehler) or correction of field distortion for individual different colors, for example when using 405 nm wavelength UV light, can be performed.

  For further advantageous configurations of the adjusting device according to the invention for adjusting the divergence and / or convergence of the light beam, reference is made to the general part of the description and the dependent claims to avoid repetition.

Finally, the above embodiment is used only for explaining the claims, and the present invention can be implemented in various forms based on the above-described principle, and is not limited to this embodiment. Let me mention that.
The piezoelectric element is structurally coupled to each lens system, and each lens system is configured to respond (follow) to the expansion and contraction of the piezoelectric element (details omitted). As the lens systems, those shown in the drawing are schematically shown, and a combination lens system can be used, and not only a convex lens system but also a concave lens system or a lens system including a concave lens can be used. Further, the drawings schematically show the solution principle of the present invention as a schematic skeleton diagram, and it is apparent that various specific mechanical configurations are possible based on this principle.

FIG. 1 shows a schematic side view of an embodiment of the adjusting device according to the invention for adjusting the divergence and / or convergence of a light beam, in which no voltage is applied to the piezoelectric element. FIG. 2 is a schematic side view of the embodiment of FIG. 1, where the piezoelectric element is shortened (in the axial direction) by applying an appropriate voltage. FIG. 3 is a schematic side view of the embodiment of FIG. 1, in which the piezoelectric element is extended (in the axial direction) by applying an appropriate voltage.

Claims (16)

An apparatus for adjusting the divergence and / or convergence of a light beam (1), at least one optical component (2) for adjusting the divergence and / or convergence of the light beam (1), and the configuration An adjustment device of the type having a positioning device (3) for the member (2),
The positioning device (3) has at least one piezoelectric element (4), an adjusting device.   2. The adjusting device according to claim 1, wherein the at least one piezoelectric element (4) has a substantially tubular region (5).   3. The adjusting device according to claim 2, wherein at least one optical component (2) is respectively arranged at at least one end of the tubular region (5).   4. The adjusting device according to claim 2, wherein the axial length of the tubular region (5) is extended and / or shortened by applying a voltage.   The adjusting device according to claim 3 or 4, wherein the focal point of the optical component (2) coincides with the reference position in a non-voltage state.   5. The adjusting device according to claim 3, wherein the focal point of the optical component (2) does not coincide with the reference position in a non-voltage state.   The adjusting device according to any one of claims 3 to 6, wherein each optical component (2) arranged in one and the other of the tubular regions (5) has the same focal length.   The adjusting device according to any one of claims 3 to 7, wherein the optical components (2) arranged in one and the other of the tubular regions (5) are configured in the same way.   The adjusting device according to any one of claims 3 to 6, wherein each optical component (2) arranged in one and the other of the tubular regions (5) has a different focal length.   10. Adjustment device according to any one of the preceding claims, wherein at least one optical component (2) is a lens.   10. The adjusting device according to claim 1, wherein at least one optical component is an achromatic lens.   12. The adjusting device according to claim 1, wherein scanning of the focal point of the light beam (1) in the optical axis direction, that is, the z-direction is executed in the microscope by the adjusting device.   13. The adjustment apparatus according to claim 1, wherein the adjustment of the image field distortion is performed in the microscope by the adjustment apparatus.   14. The adjusting device according to claim 1, wherein correction of chromatic aberration or field distortion is performed on each color by the adjusting device in a microscope.   The microscope provided with the adjustment apparatus as described in any one of Claim 1-14.   A scanning microscope comprising the adjusting device according to any one of claims 1 to 14.

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