Technical Field

The invention relates to an ophthalmologic microscope, in particular a slit-lamp microscope, with a joystick as a user-controllable input device.

Background Art

WO 2010/006741 describes an ophthalmologic microscope having a joystick as an input element. The user can operate the joystick for controlling numerous functions of the device. The joystick is therefore provided with buttons, sliders, and a wheel. However, such elements are prone to contamination and hard to clean, which makes proper maintenance of the microscope difficult.

Disclosure of the Invention The problem to be solved by the current invention is to provide a microscope of this type, in particular a slit-lamp microscope, that is easier to maintain.

This problem is solved by the microscope of claim 1.

Accordingly, the microscope comprises at least the following parts: - A microscope unit: This is the part of the microscope that observes and magnifies the eye to be examined.

- A control unit: The control unit is an electronic unit controlling parts of the microscope.

- A joystick. The joystick forms a user-controllable input device adapted to control the microscope. It is may be monitored by the control unit to detect how the user operates it.

According to the invention, the joystick comprises a plurality of touch sensors. In contrast to mechanical input controls, touch sensors are less prone to contamination and can be cleaned easily, which simplifies the maintenance of the de- vice. The joystick may comprise a base, which is typically at rest, and a tiltable body, which is the part operated by the user. The tillable body is mounted on the base and its axis is held therein.

The joystick may comprise a touch sensor surface with a plurality of the touch sensors arranged at (e.g. under) the touch sensor surface. Further touch sensors may be arranged at locations away from the touch sensor surface.

Advantageously, the touch sensor surface is flat, which makes it easier to access and to understand its functions. In this context, “flat” advantageously expresses that there is at least one flat plane for which a closest distance d between any point on the touch sensor surface and said plane is smaller than a tenth of the smallest diameter of the touch sensor surface.

Alternatively, the touch sensor surface may be curved, in particular convex.

The body of the joystick may further comprise the following ele- ments:

- A first end: This is the part pivotally connected to the base.

- A second end opposite to the first end: The joystick axis extends between the first and the second end.

In this case, the touch sensor surface may be located at the second end and extend transversally to the joystick axis. This makes the touch sensor surface easily accessible to the user, e.g. by using a thumb or index finger while holding the joystick.

The body of the joystick may further comprise a rotatable wheel extending around the joystick’s axis. This wheel may form an input device monitored by the control unit of the microscope. It can be located between the first end and the touch sensor surface at the second end, which allows the user to operate the wheel, e.g. with a thumb, and to still access the touch sensor surface above it, e.g. with an index finger.

The touch sensor surface may comprise a first haptic contour ex- tending along a first direction and a second haptic contour extending along a second direction. The first and second directions extend transversally to each other. The touch sensors at the touch sensor surface are adapted to distinguish between a plurality of finger positions along the first and second haptic contours.

This allows the user to place his finger at different positions along the contours, in both the first and the second directions, and therefore to use the touch sensor surface as a two-dimensional input device. The contours allow the user to dis tinguish between the two directions easily, without even looking at the joystick. Advantageously, the first and second directions of the haptic con tours extend under an angle of at least 70°, in particular under an angle of 90°, in or der to make them easily distinguishable.

In order to make the microscope easy to operate for left-handed and right-handed users, the first and second directions may be arranged at 45° to the optical axis of the microscope unit. In more precise terms, in the neutral position of the joystick (i.e. when the user does not apply a force to it), the first and the second directions are at an angle of at least 40° in respect to the optical axis. Advantageously, this angle is 45°.

(If the touch sensor surface is non-parallel to the optical axis, said angle must be measured by viewing the touch sensor surface from a direction perpendicular to the center of the touch sensor surface and projecting the optical axis into a plane perpendicular to the viewing direction and then measuring the angles between the projected axis and the first and second directions, respectively.)

The touch sensors can be used to control various settings of the microscope.

To name a few of them, the control unit of the microscope may be adapted to carry out one or more of the following functions of the device:

- Triggering the camera of the microscope for recording an image upon tapping at least one of the touch sensors, in particular upon tapping the touch sensor surface.

- Changing the zoom factor of the microscope upon detecting the movement of a finger along a first direction of the touch sensor surface.

- Changing between microscope presets as e.g. stored in the control unit upon moving a finger along a second direction of the touch sensor surface. Such settings may e.g. include parameters for illumination and/or zoom factor.

- Changing a first setting of the microscope (e.g. the vertical position of the microscope device and/or of a headrest) when rotating the wheel on the joystick while the user is not touching said touch sensors and changing a second (different) setting (such as the zoom factor) of the microscope when rotating the wheel while the user touches at least one of the touch sensors.

- Changing the geometry of the light field from the illumination source of the microscope in response to a sliding motion on the touch sensors.

Further examples of settings that can be controlled are provided be- low. Brief Description of the Drawings

The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description refers to the annexed drawings, wherein: Fig. 1 shows a lateral view of a slit lamp microscope,

Fig. 2 shows a top view of the microscope (with the slit lamp arm pivoted in respect to the microscope’s optical axis),

Fig. 3 shows a view of a first embodiment of a joystick,

Fig. 4 shows a view of a second embodiment of a joystick,

Fig. 5 shows a sectional view through a joystick along line A-A of

Fig. 6,

Fig. 6 shows a top view of the joystick along the joystick axis,

Fig. 7 shows a view of a wheel and the magnets,

Fig. 8 shows a bottom view of a sensor circuit board of a joystick, and

Fig. 9 shows a block circuit diagram of some components of the microscope.

Modes for Carrying Out the Invention

Definitions

Any angle mentioned herein is understood to be within an accuracy of +/-10°, in particular +1-5°.

The general term “finger” also includes the user’s thumb.

Microscope

Figs. 1 and 2 show an embodiment of an ophthalmologic microscope, namely a slit lamp microscope.

The device shown here has a base 1 resting e.g. on a desk, a horizontally displaceable stage 2 mounted to base 1, a first arm 3, and a second arm 4.

The arms 3 and 4 are mounted to stage 2 and pivotal about a common vertical pivot axis 5.

Arms 3 and/or 4 are e.g. manually operated, i.e. their angular position is changed manually, or they may be provided with electric angular actuators to operate them automatically. The device may further include a headrest 7 mounted to base 1 for receiving the patient’s head.

Arm 3 carries a microscope unit 8, and arm 4 carries a first illumination source 9.

First illumination source 9 may e.g. be a conventional slit lamp as known to the skilled person, adapted to project a slit-shaped light beam onto the eye 10 to be examined.

Microscope unit 8 has an optical axis 12 along which its entry objective 14 projects the image of an eye 10 to be examined. The image is projected, directly and/or via further components, onto a camera 16 and/or an eyepiece 18.

Microscope unit 8 may be provided with changeable zoom optics 15 for changing the optical magnification. Changeable zoom optics 15 may include continuously changeable zoom optics or stepwise changeable zoom optics (e.g. imple mented as a Galilean optical system).

For quantitative measurements, the device advantageously is equipped with camera 16 while eyepiece 1 is optional. A beam splitter 20 may be arranged to spilt light between these components.

A plurality of microscope light sources 22a, 22b may be arranged on microscope unit 8 and movable together with it. They form a second illumination source 22. Advantageously, they are located around entry objective 14 and/or on a side of microscope unit 8 that faces eye 10.

First illumination source 9 comprises a light source 30, a modulator 32 and imaging optics 34.

Light source 30 can e.g. comprise several units emitting different wavelengths, e.g. in the red, green, blue, and infrared range of the optical spectrum. These units can be controlled separately in order to change the color of light source 30.

Modulator 32 is a spatial light modulator defining the cross section of the illumination field generated by first illumination source 9. It may e.g. be one of the solutions described in US5943118, such as a liquid crystal display or a controllable micro-mirror array.

Imaging optics 34 projects the light from modulator 32 onto the anterior surface of eye 10, e.g. via a mirror 36 mounted to arm 4.

Illumination source 9 can be arranged above or below mirror 36.

The microscope further comprises a control unit 40. Control unit 40 may be incorporated at least in part into the microscope and/or it may at least in part be a separate device. In addition, the microscope comprises a joystick 42 for controlling various functions thereof.

Joystick 42 is advantageously mounted to stage 2, but it may also be mounted to another part of the microscope or comprise its own stand. The design and function of joystick 2 will now be described in further detail.

Joystick Design

The Design of the joystick 42 is shown in Figs. 3 - 6.

As best seen in Fig. 5, joystick 42 comprises a base 44 and a body 46 tiltably mounted to base 44. in the embodiment of Fig. 1, base 44 is e.g. mounted to stage 2.

Body 46 is elongate along a joystick axis 48, which is typically upright as defined above. It has a first end 50 and a second end 52, with joystick axis 48 extending between them. In the shown embodiment, first end 50 comprises a spherical foot section 54 held in a spherical seat 56 of base 44, which allows to tilt body 46 in respect to base 44 in two dimensions, such as the two horizontal directions x and z as shown in Fig. 2.

In one embodiment, body 46 may be held in a given position by frictional forces between body 46 and base 44.

At second end 52, a touch sensor surface 58 is provided on body 46. It extends transversally to joystick axis 48.

Advantageously, the angle between the center of touch sensor surface 58 and joystick axis 48 is at least 60°. Advantageously, it is 90°. A plurality of touch sensors 60 are located at touch sensor surface

58, e.g. on a board below touch sensor surface 58 as shown in Fig. 5.

The touch sensors 60 are advantageously designed as a two-dimensional array of individual touch sensors 60a (cf. Fig. 9 spanning the touch sensor surface, i.e. extending all across the touch sensor surface. The touch sensors 60 allow a spatially resolved detection of the position of the operator’s finger on touch sensor surface 58. Together with a suitable controller, they may also allow to detect gestures, such as tapping or dragging, and/or multi-finger gestures.

As best seen in Fig. 6, the present embodiment of touch sensor sur- face 58 comprises contours 62a, 62b, which help the user to properly place his fingers. In the shown embodiment, there are first haptic contours 62a extending along a first direction Ml and second haptic contours 62b extending along a second direction M2. They provide guides for the user’s finger(s). Accordingly, the touch sensors 60 of the touch sensor surface 58 are designed to distinguish between a plurality of finger positions, e.g. at least between ten different finger positions, along the first and second haptic contours 62a, 62b.

In the embodiment of Fig. 6, and also in the embodiments of Figs. 3 and 4, the haptic contours 62a, 62b are formed by the edges of a cross 64.

Advantageously, cross 64 is a cross-shaped recess in touch sensor surface 58 because such a recess provides inherent guidance of the fingers along the main directions of the cross 64. Alternatively, cross 64 may also be a raised structure projecting above touch sensor surface 58.

For the reasons mentioned above, first direction Ml and second direction M2 extend transversally to each other, with their smallest mutual angle a (as shown in Fig. 6) being at least 70°. Advantageously, the angle a is 90°.

As best seen in Fig. 3, and for the reasons mentioned above (i.e. for the joystick to be easily operated with the left as well as the right hand) the first and second directions Ml, M2 each are at an angle pi and b2 in respect to optical axis 12 and therefore to direction z in Fig. 3, with bΐ and b2 being both at least 40°, in particular of 45°. In this context, the angles bΐ and b2 are defined as the smallest angles between the directions Ml, M2, respectively, and direction z, i.e. the direction of the optical axis 12.

It must be noted, though, that the directions Ml and M2 may e.g. also correspond to the directions x and/or z, as shown for the embodiment of Fig. 4.

In yet another embodiment, touch sensor surface 58 may be rotata ble about joystick axis 48, which allows e.g. the user to align it optimally for her/his individual needs.

The embodiments of Figs. 3, 4 and 5ff all comprise a rotatable wheel 66 located between first end 50 and second end 52 of joystick 42.

Wheel 66 extends around joystick axis 48 and is advantageously coaxial thereto. It can be rotated by the user to change current settings of the microscope and/or to operate its software.

Joystick 42 further comprises a rotation sensor coupled to wheel 66. This sensor may e.g. be optical, mechanical, or magnetic.

In the embodiment shown in Figs. 5 - 8, the rotation sensor is magnetic and comprises several permanent magnets 68 mounted to rotate with wheel 66 as well as at least two magnetic sensors 70, e.g. Hall effect sensors, located stationary in body 46 of the joystick (see Figs. 7, 8).

Advantageously, the permanent magnets 68 are arranged at regular azimuthal intervals f along the azimuthal circumference of wheel 66. Advantageously, and as shown in Fig. 6, there is an even number of permanent magnets 68 altematingly polarized in directions parallel and anti-parallel to joystick axis 48. They generate a magnetic field that alternates, along the direction of joystick axis 48, as a function of the azimuthal position f (see Fig. 7 for an illustration of azimuthal position f. The sensors 70 are advantageously arranged, in respect to joystick axis 48, under a mutual azimuthal angle F (see Fig. 8), with F/f not being an integer number, advantageously with

0.25 < & o(F/f) < 0.75, (1) in particular with b¾ϋ(F/f) = 0.5. (In this context, frac(x) is a function returning the fraction to the right of the decimal point of x.)

By choosing F/f not to be an integer number, it is possible to distinguish, for any azimuthal position of wheel 66, the direction into which it is being rotated.

In the embodiment of Figs. 7 and 8, there are four permanent magnets 68, i.e. f = 90°, and the mutual azimuthal angle F is chosen to be 45°, i.e. frac^Aji) = 0.5.

As can be seen in Fig. 7, the permanent magnets 68 may e.g. be mounted in axial bores 72 of wheel 66.

The magnetic sensors 70 may be arranged on a printed circuit board 74 located within body 46 laterally within wheel 66. Circuit board 74 may hold further components, in particular electronic circuitry for processing the signals from the touch sensors 60. For easy operation, wheel 66 is advantageously located adjacent

(e.g. within a distance of less than 5 mm, in particular of less than 1 mm) to touch sensor surface 58, such that the user may e.g. operate wheel 66 with his thumb and touch sensor surface 58 with his index finger.

Joystick Function

Fig. 9 shows a block circuit diagram of some parts of the micro- scope. In particular, Fig. 9 shows the touch sensors 60, which are con nected to processing circuitry 76. Processing circuitry 76 is advantageously adapted to detect the position of at least one finger on touch sensor surface 58, to detect swiping or tapping operations, and/or to detect multi-finger gestures, such as pinching. Fig. 9 further shows control unit 40, e.g. comprising a microprocessor 80 and memory 82 connected to processing circuitry 76.

Control unit 40 is also connected to the magnetic sensors 70 for de tecting a rotation of wheel 66 as well as to any further input elements 80 arranged on joystick 42 or elsewhere on the microscope. Control unit 40 is advantageously also connected to a display 84 for showing operating information of the microscope as well as fur displaying images or videos recorded by means of camera 16. For the latter, control unit 40 is also connected to camera 16. Display 84 may e.g. be arranged next to joystick 42 as shown in Figs. 3 and 4. Finally, control unit 40 is connected to a plurality of actuators 86a -

86d for controlling the functions of the microscope. These may e.g. include at least one of the following actuators:

- A driver for controlling light source 30 and/or modulator 32.

- A driver for controlling zoom optics 15. - A driver for controlling the height of headrest 7.

- Drivers for setting the x- and z-positions of stage 2 in respect to base 1.

The user can control at least some functions of the microscope by operating joystick 42. The following are some examples of control operations that the software and hardware of control unit 40 can be adapted to support:

- The displacement of stage 2 along the directions x and z can be controlled by tilting joystick 42.

- Camera 16 can be triggered for recording at least one image (e.g. a still image or a video sequence) by tapping at least one of the touch sensors 60, in particular by tapping touch sensor surface 58.

- The zoom factor of the microscope may be changed upon moving a finger along first direction Ml of touch sensor surface 58. In other words, when the user moves e.g. a finger along first Ml direction of cross 64, control unit 40 changes the settings of zoom optics 15. - Memory 82 of control unit 40 may hold several different microscope presets, with each of said presets comprising setting parameters for various actuators of the microscope, e.g. different illumination settings, zoom settings, image recording settings, etc. In this case, control unit 40 may be adapted to perform the function of changing between such microscope presets upon detecting the movement of a finger along second direction M2 of touch sensor surface 58.

- The touch sensors 60 may also be used as a modifier for operating wheel 66, i.e. operating wheel 66 has a different effect when the user does not touch the touch sensor surface from when the user does touch it. In other words, control unit 40 may be adapted to carry out the function of changing a first setting of the microscope when rotating wheel 66 while not touching the touch sensors 60 and changing a second (different) setting of the microscope when rotating wheel 66 while touching at least one of the touch sensors 60. For example, the first setting may be the height of headrest 7 and the second setting may be the zoom setting of zoom optics 15.

- If the microscope comprises an adjustable light illumination field, such as e.g. embodied by modulator 32, a sliding motion on the touch sensors may be used to change the geometry of the light field, such as the width of a slit-shaped light field and/or its position.

Notes

As mentioned, the touch sensors 60 at touch sensor surface 58 allow a spatially resolved detection of the position of the operator’s finger on touch sensor surface 58.

In order to be easily operated by the user, the array of touch sensors comprises at least some touch sensors that have a mutual distance of at least 1 cm, in particular of at least 2 cm. In particular, the smallest convex hull around all touch sensors of the touch sensor surface is at least 1 cm ² , in particular at least 2 cm ² .

The spatial resolution of the array of touch sensors is advantageously better than 1 mm in order to detect even small movements and to provide a large spatial resolution.

In addition or alternatively to the array of touch sensors at touch sensor surface 58, there may be other touch sensors located on body 46 of joystick 42. For example, wheel 66 may be replaced by a second, annular touch sensor surface 58, e.g. designed as an annular groove, with its own array of touch sensors, adapted to detect a plurality of different finger positions along it. While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.