Filter changing device for optical beam paths

Abstract

The invention relates to a filter changing device (1) for optical beam paths (S, S1, S2). This device comprises a first filter wheel (5) and a second filter wheel (6) for holding and positioning a number of optical elements (8) in an optical beam path (S, S1, S2), each of which can be moved in a controlled manner along sections of a circular path. Furthermore, a common drive (2) for the controlled generation of a movement of the filter wheels (5, 6) along their respective circular path, wherein the drive (2) is connected to the first and second filter wheels (5, 6) via a gear (3, 4), each gear (3, 4) being designed with a drive direction (AR) and a freewheel direction (FR), and the drive direction (AR) and the freewheel direction (FR) of the gears (3, 4) of the first filter wheel (5) and the second filter wheel (6) respectively being designed to oppose one another. The filter changing device (1) is characterized in that the sections of the circular paths each cover an angular range of more than 180°; each freewheel in the freewheel direction (FR) is unlimited, and a filter wheel (5, 6) delivered to a current position in the drive direction (AR) is held at the current position by means of the gear (3, 4) and is moved further from the current position upon a renewed flow of force in the drive direction (AR).

Description

[0001] The invention relates to a filter changing device for optical beam paths according to the preamble of the main claim.

[0002] In optical systems, especially in microscopes and other systems for stereoscopic applications, the goal is to make components as compact and simple as possible. For optical systems, especially for their illumination and / or detection beam paths, there is often a requirement to be able to move different filters or apertures into or out of the beam paths. Furthermore, it can be advantageous to combine existing optical elements as needed, for example, using rotatable filter wheels.

[0003] To allow for a free combination of the optical elements on the filter wheels, each filter wheel can have its own drive. The disadvantages of this approach are the required number of components and the space required.

[0004] One possibility of controlling a total of three filter wheels with just one drive and at the same time providing a certain combinability of the optical elements arranged on the filter wheels is known from EP 3 851 893 A1. There, a middle of three filter wheels is driven, while the other two are not connected to an active drive. The filter wheels have driving pins and segment-shaped grooves or slots that are coordinated with one another such that when the middle filter wheel rotates in a first direction, only the first filter wheel is driven. When rotated in a second direction, only the third filter wheel is driven. The grooves or slots therefore each provide freewheeling for one of the filter wheels in one direction of rotation of the middle filter wheel.

[0005] However, with this solution, the number of positions to which one of the filter wheels can be moved is limited, particularly due to the limited dimensions of the grooves or slots. Furthermore, each of the two non-actively driven filter wheels is returned to its original position by a reset device after a drive operation, in order to be able to use the respective freewheel again.

[0006] The invention is based on the object of proposing a possibility for the controlled driving of several filter wheels with only one drive, which is improved compared to the prior art.

[0007] The problem is solved by the subject matter of the independent claim. Advantageous further developments are the subject matter of the dependent claims.

[0008] A filter changing device for optical beam paths comprises a first filter wheel and a second filter wheel for holding and positioning a number of optical elements or components, such as color filters, polarizing filters, optical lenses, prisms, diaphragms and / or masks. Selected filter wheels can be arranged in an optical beam path by moving the filter wheels together with the respective optical elements in a controlled manner along sections of a circular path and advancing them to a desired position. The filter changing device has a common drive for the controlled generation of a movement of the filter wheels along their respective circular path. The common drive is connected to the first and second filter wheels via a gear mechanism.Each of the gears can be operated in a drive direction and a freewheeling direction, with the drive direction and freewheeling direction of the gears of the first filter wheel and the second filter wheel, respectively, being opposite to each other. In one drive direction of the gear, the associated filter wheel is rotated by a corresponding angular amount, while in the freewheeling direction, no drive force is transmitted from the common drive to the respective filter wheel by the gear.

[0009] A filter changing device according to the invention is characterized in that the sections of the circular paths each cover an angular range of more than 180°. The filter wheels can be moved over a large angular range, which advantageously increases their flexible usability compared to prior art solutions. Furthermore, each freewheel is unlimited in the freewheeling direction. A filter wheel can therefore potentially be moved over any angular range, up to multiple complete revolutions, in freewheeling. Furthermore, a filter wheel that has been moved to a current position (also: angular or rotational position, rotational setting) in the drive direction is held in the current position by the action of the gearing and, when driven again in the drive direction, is moved further from the current position.

[0010] In further embodiments of the filter changing device according to the invention, the angular ranges of the circular paths are at least 270°, in particular at least 360°.

[0011] Holding at the current position can, for example, be achieved by the gear mechanism, which remains in positive and / or non-positive contact with the filter wheel and is held there due to its mechanical inertia and / or by the action of a braking device (see below).

[0012] The core of the invention is that, thanks to the aforementioned design measures and a single common drive, the filter wheels are actually moved independently of one another, allowing any desired configuration to be set relative to one another. The large angular range of the drive direction and the unlimited freewheeling enable maximum flexibility. The ability to start a subsequent movement in the drive direction directly from a previously assumed current position, without first having to return to a starting position, as described in the prior art, advantageously enables fast and very precise delivery to a new current position. The high precision of the delivery and the theoretically unlimited number of possible positions also allow a large number of optical elements to be provided on the filter wheels.For example, a filter wheel of a filter changing device according to the invention can hold 6, 8, 9, 10 or more optical elements.

[0013] The optical elements are held in designated apertures (filter receptacles, hereinafter referred to as "receptacles"). They can be inserted, screwed, or held in place by means of a retaining device. The filter wheel positions are advantageously standardized, allowing each filter receptacle to be fitted with a correspondingly designed optical element.

[0014] It is also possible to provide a predetermined and fixed configuration of the filter wheels. However, it is advantageous to arrange the optical elements interchangeably within the filter wheels. It is also possible to leave individual positions on the filter wheels free, for example, to allow for unobstructed beam passage when the respective filter holder is blocked by an optical beam path.

[0015] In further embodiments of the invention, the filter wheels can also have individual positions that differ from a standardized filter mount, for example, in terms of their size and / or angular position. For example, individual mounting options for the optical elements to be held can be provided or retrofitted.

[0016] The filter wheels can optionally also have reference markers, which can be used to determine a current position and / or a defined zero position. As is known from the prior art, such reference markers can be, for example, openings in the filter wheels, notches in the edge areas, protrusions (protrusions, flags) protruding from the filter wheel, and / or reflective or otherwise optically detectable components. For position control, pedometers, light barriers, and / or optical sensors (cameras), for example, can be used.

[0017] In order to enable automated and precise operation of the filter changing device according to the invention, the common drive (hereinafter also referred to as "drive") is advantageously designed as a motor drive, for example in the form of a stepper motor, a DC motor with encoder, or another motor drive, preferably with integrated position monitoring. The drive can advantageously be controlled using control commands from a controller. For this purpose, motor control boards with microcontrollers or FPGAs (field programmable gate arrays) can be used, for example, which in turn are controlled by a higher-level control computer.

[0018] The first and second gears of the filter changing device according to the invention can be in contact with the filter wheel, for example, either by means of a gear drive or by means of a friction drive. In the first case, a positive connection would be created between the gear and the filter wheel, while in the second case, a non-positive connection would be created. Power transmission via belts, in particular a toothed belt, is also conceivable.

[0019] The areas of the filter wheels that serve to transmit drive forces, and optionally braking forces (see below), can be formed in sections or circumferentially on their outer end face and / or on at least one of their side surfaces, advantageously in the area of ​​the outer edge. These areas can be teeth or raceways of a friction wheel drive.

[0020] To prevent unwanted crosstalk between the movements of the filter wheels, each filter wheel can be assigned a braking device. The term "braking device" can be understood broadly. For example, the first or second gear itself can also act as a braking device. If, for example, the teeth of a gear mechanism designed as a toothed transmission are continuously meshing with one another, the filter wheel is prevented from unwanted rotation. It is advantageous to adjust the required braking torque by coordinating the frictional forces between the gear members and their bearings. Furthermore, additional components such as rotation brakes or locking devices can be present and used.

[0021] The filter changing device according to the invention can be advantageously used in optical arrangements such as microscopes, illumination or detection devices, zoom systems, or optical measuring and testing devices. In one embodiment, the filter wheels can be placed in a common beam path. In a further embodiment of the invention, each of the filter wheels can be placed in different beam paths. The beam paths can be, for example, illumination beam paths and / or detection beam paths.

[0022] To position the filter wheels in a common beam path and to enable a compact design, the filter wheels can be arranged on a common rotation axis. In contrast, the filter wheels can be arranged on different rotation axes if they are to be positioned for two different beam paths.

[0023] The invention is explained in more detail below using exemplary embodiments and figures. They show: Fig. 1 schematic representations of a first embodiment of a filter changing device according to the invention in a side view and in a side view of the existing filter wheels; Fig. 2 a schematic representation of a second embodiment for arrangement on two different beam paths; and Fig. 3 a schematic representation of a process of moving a filter wheel to a new current position by means of a filter changing device according to the invention.

[0024] In the figures relating to the embodiments, identical technical elements are provided with the same reference numerals.

[0025] As essential elements of a filter changing device 1 according to the invention there are a drive 2 as well as a first gear 3 and a second gear 4, which can be driven by the action of the drive 2, as well as a first filter wheel 5 and a second filter wheel 6 ( Fig. 1). Shown as an example is a drive shaft 2.1 for transmitting power from the drive 2 to the gears 3, 4. The first gear 3 is in contact with the first filter wheel 5, which enables power transmission from the first gear 3 to the first filter wheel 5. The same applies to the second gear 4, which is connected to the second filter wheel 6. The drive 2 is advantageously a motor that can be controlled by a controller 9 with regard to its respective direction of rotation and the angular range covered in each case. The filter changing device 1 can be a component of a microscope 11 (not shown in detail).

[0026] Both gears 3 and 4 are equipped with a freewheel in one direction of their mechanical power flow (freewheel direction FR), while in the opposite direction, power is transmitted from drive 2 to the respective gear 3, 4 (drive direction AR). Both directions are symbolized by arrows of different line types next to the reference symbol.

[0027] The gears 3, 4 have, for example, a drive wheel, for example in the form of a gear or a friction wheel, in order to transmit a force to the filter wheel 5 or 6 assigned to the respective gear 3, 4.

[0028] The middle part of the figure shows the filter changing device 1 in a view of the respective circumferential end faces of the gears 3, 4 and the parallel filter wheels 5, 6. The two filter wheels 5, 6 can be rotated about a common axis of rotation D and through angular ranges specified by the gears 3, 4.

[0029] The filter wheels 5, 6 have a plurality of filter receptacles 7, which can, for example, variably accommodate and hold various optical elements 8 such as filters, lenses, diaphragms, prisms, masks and / or polarizing elements (center sub-figure). It is also possible to leave individual filter receptacles 7 unequipped in order to allow unaffected passage of radiation (see, for example, filter wheel 5, upper filter receptacle 7). For reasons of clarity, only two of the existing filter receptacles 7 are shown as examples in the middle sub-figures. In the exemplary embodiment, the filter receptacles 7 are arranged on a circular path (see side views, symbolized by a broken circle). The filter receptacles 7 shown in the example in the 180° position are aligned with a common beam path S.Radiation propagating along the beam path S passes through the optical elements 8 located in the beam path S and is influenced by them according to their properties. By rotating at least one of the filter wheels 5, 6 to a new current position, a different combination of optical elements 8 and / or unoccupied filter receptacles 7 is placed in the beam path S.

[0030] In order to determine the current rotational position of the filter wheels 5, 6, in addition to step counters on the drive 2 or on the gears 3, 4, reference marks 10 can also be provided on the filter wheels 5, 6. For example, a projection ("flag") protruding from the edge is provided on the first filter wheel 5, and an opening is provided on the second filter wheel 6 as a reference mark 10. Their position or their passage through a predetermined zero position can be detected, for example, by means of a tactile sensor, an induction sensor, a camera, or a light barrier (neither shown). Other possible reference marks 10 can be implemented as reflective elements. Other arrangements, shapes, and dimensions of reference markers 10 are also possible.

[0031] The drive directions AR and the freewheel directions FR of gears 3, 4 are opposite to each other, as illustrated by the arrows in the middle part of the figure. For example, if the drive shaft 2.1 is rotated counterclockwise from the left side, the first gear 3 operates in the drive direction AR and the first filter wheel 5 is moved clockwise by a certain distance.

[0032] Meanwhile, the second gear 4 is in the freewheel direction FR, so that the second filter wheel 6 remains in its current position. If the direction of the power flow on the part of the drive 2 changes, in this example, a change in the direction of rotation of the drive shaft 2.1, the second filter wheel 6 is driven and the first filter wheel 5 remains in its current position (rotational position, see also below for Fig. 3).

[0033] In Fig. Figure 2 shows a second embodiment of a filter changing device 1 according to the invention, whose filter wheels 5, 6 are each positioned facing a different beam path S1 or S2, respectively. For this purpose, the filter wheels 5, 6 are positioned side by side. In further possible embodiments, the filter wheels 5, 6 can be arranged parallel to each other but laterally offset from each other.

[0034] The operation of the filter changing device 1 according to the invention is shown in Fig. 3 using the example of the first gear 3 and the first filter wheel 5. In the left-hand part of the figure, the first filter wheel 5 is positioned at a current position, in which, for example, a filter holder 7 with an optical element 8 (shown in dotted lines) is in a 180° rotational position.

[0035] It would be possible to move the second filter wheel 6 (not shown) to a new current position if the drive 2 is controlled in such a way that it drives the second gear 4 in its drive direction AR while the first gear 3 is operated in its freewheel direction FR. The first filter wheel 5 thus remains stationary, while the second filter wheel 6 is moved accordingly.

[0036] To move the first filter wheel 5 from its current position to a new position (rotational position, rotational setting), the drive 2 is controlled by control commands from the controller 9 so that it transmits a force to the first gear 3 in its drive direction AR. Depending on the desired new position of the first filter wheel 5, the first gear 3 is moved by a specific angle according to the gear ratio (illustrated with line marks).

[0037] Neither the filter wheels 5, 6 nor the gears 3, 4 need to be returned to their original position. Due to the unlimited freewheeling of the gears 3, 4, each of the filter wheels 5, 6 can be rotated through any desired angle, even more than 360°. At the same time, the gears 3, 4 remain in contact with the filter wheels 5, 6, thus preventing unintentional adjustment of one filter wheel when the other filter wheel is moved. Reference symbol 1 filter changing device 2 drive 2.1 Drive shaft 3 first gearbox 4 second gearbox 5 first filter wheel 6 second filter wheel 7 Filter wheel, eye, filter holder 8 optical element 9 Control 10 Reference mark 11 Microscope AR drive direction D axis of rotation FR freewheel direction S, S1, S2 beam path QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 851 893 A1

[0004]

Claims

[1] Filter changing device (1) for optical beam paths (S), comprising - a first filter wheel (5) and a second filter wheel (6) for holding and positioning a number of optical elements (8) in an optical beam path (S, S1, S2), which can each be moved in a controlled manner along sections of a circular path; - a common drive (2) for the controlled generation of each of the filter wheels (5, 6) along their respective circular path, wherein ◯ the drive (2) is connected to the first and second filter wheel (5, 6) via a gearbox (3, 4) respectively, each gearbox (3, 4) being designed with a drive direction (AR) and a freewheel direction (FR), ◯ the drive direction (AR) and the freewheel direction (FR) of the gears (3, 4) of the first filter wheel (5) and the second filter wheel (6) respectively are designed in opposite directions. characterized by , that - the sections of the circular paths each cover an angular range of more than 180°; - each freewheel in the freewheel direction (FR) is unlimited, and - a filter wheel (5, 6) moved to a current position in the direction of drive (AR) is held at the current position by means of the gearbox (3, 4) and is moved further from the current position when a new force flow is applied in the direction of drive (AR). [2] Filter changing device (1) according to claim 1, characterized by ., that the angular ranges of the circular paths are at least 270°, in particular at least 360°. [3] Filter changing device (1) according to claim 1 or 2, characterized by , that the drive (2) is a motor drive. [4] Filter changing device (1) according to one of the preceding claims, characterized by, that each filter wheel (5, 6) is assigned a braking device, the action of which prevents crosstalk between movements of the filter wheels (5, 6). [5] Filter changing device (1) according to one of the preceding claims, characterized by , that the gears (3, 4) are in contact with the filter wheel (5, 6) by means of a gear drive each. [6] Filter changing device (1) according to one of the preceding claims, characterized by , that the gears (3, 4) are in contact with the filter wheel (5, 6) by means of a friction wheel drive each. [7] Filter changing device according to one of the preceding claims, characterized by , that the filter wheels (5, 6) are arranged on a common axis of rotation (D). [8] Filter changing device (1) according to any one of claims 1 to 6, characterized by , that the filter wheels (5, 6) are arranged on different axes of rotation (D). [9] Microscope (11) with a filter changing device (1) according to one of the preceding claims.

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