EP4493973A2

EP4493973A2 - Directly coupled multichannel illuminating device

Info

Publication number: EP4493973A2
Application number: EP23727064.0A
Authority: EP
Inventors: DR. Viktor Sebestyén VARGA; Vilmos MARSÓ
Original assignee: Starlightengine Kft
Current assignee: Starlightengine Kft
Priority date: 2022-03-16
Filing date: 2023-03-10
Publication date: 2025-01-22
Also published as: HUP2200079A1; WO2023175361A2; WO2023175361A3

Abstract

The invention relates to a directly coupled multichannel illuminating device (10) for a microscope (200), which device (10) comprises: - a heatsink (11) having a substantially flat back (11 a) and provided with fins (20) on a side (11 b) opposite to the back (11 a), - a plurality of light sources (16), each of which is connected to the back (11 a) of the heat sink (11) by means of heat conducting blocks (17), - a control electronics (30) connected to the light sources (16) and adapted to operate the light sources (16), - an optical connector (40) fixed to the heat sink (11) and extending through the heat sink (11) towards the side (11 b) opposite to the back (11 a), said optical connector (40) being formed as a light guide channel having a first end (40a) facing the back (11 a) and a second end (40b) facing the microscope (200), - an inclined mirror (50) arranged at the first end (40a) of the optical connector (40) at the back (11a) of the heat sink (11) and adapted to guide the light of the light sources (16) through the optical connector (40), and - a rear cover (60) arranged at the back (11 a) of the heat sink (11 ), connected to the heat sink (11 ) and defining an interior space (100) together with the back (11a) of the heat sink (11).

Description

Directly coupled multichannel illuminating device

The invention relates to a directly coupled multichannel illuminating device for microscopes.

In fluorescence microscopy, light sources with the highest possible light density are used, which are sufficiently strong in the blue as well as in the UV range. High light density is needed for the special requirements of microscopy, where typically areas of 1 square millimetre or less need to be illuminated.

In the last decade, the luminous efficiency of LEDs has increased to such an extent that the use of LEDs in fluorescence microscopy has become a realistic option. The advantage of LEDs is that their efficiency is much higher than that of the mercury vapour lamps used in the past. In microscope lamps using LEDs, the electromagnetic radiation corresponding to the emission peaks of the mercury vapour lamp is produced by a number of LEDs in multiple channels, illuminated at different wavelengths. In fluorescence microscopy, usually 3 different fluorescent dyes are used simultaneously on a sample, but in some research more than this may be used. It can vary from sample to sample which of the 3 dyes are used, so prior art solutions usually use lamps with 4 to 16 channels.

The drawback of multichannel illuminating devices is that multiple light sources together generate significant amounts of heat, which requires an advanced cooling system to dissipate. For existing multichannel illuminating devices, cooling is practically only possible by using active cooling fans. In microscopy, however, vibrations generated by the motors tend to cause problems. The fans reduce image quality by continuously generating vibrations over the hundreds of milliseconds of exposure time. A partial solution to this problem is the use of lamps attached to a liquid light guide (LLG), also known as a fiber, where the illuminator is placed away from the microscope so that the fan vibrations can be well isolated. Examples of such a fiber-coupled lamp are the SPECTRA from Lumencor or the pE-4000 from Cooiled. The electromagnetic radiation produced by these lamps are guided to the microscope by means of a liquid light guide, but this is not the best way to use the light. A fluorescent lamp should be good in the wavelength range of approximately 365 - 750 nm. However, none of the currently known light guides are well suited to this, as even at the optimal wavelengths 20-50% of the light is lost. A further problem with light guides is that they are 3-5 mm in diameter, so that the surface area illuminated at the end is too large and cannot be optimally collected in the microscope. This light loss requires higher power light sources, which produce even more heat. More fans and a more complex cooling system are needed to dissipate the higher heat, which further increases costs.

Because of the above disadvantages of fibre-coupled lamps, solutions with one or only a few channels try to connect the illuminating device directly to the microscope via an optical connector (adapter) (so-called directly coupled lamps). In this case, expensive liquid light guides can be omitted, so that the above-mentioned light loss does not occur. For the latter reason, lower power light sources, which produce less heat, are sufficient to achieve the same illuminating effect. It should be noted, however, that the known multichannel directly coupled lamps are also actively cooled by fans, as is the case with the Hyper E600 from Yodn or the pE- 300 from Cooiled. The lamp housing is provided with ventilation slots through which the fans circulate air through the lamp. One disadvantage of this is that the vibrations generated by the fans are transmitted directly to the microscope due to the direct coupling, thus degrading the quality of the imaging. Another disadvantage is that the dust from the air sucked in by the fans will over time build up on the light sources, the optical elements in the lamp and the electronics. This requires periodic disassembly and maintenance of the lamp. A further disadvantage of these solutions is that due to the design of the illuminating device, the optical connector and the microscope are subjected to relatively high forces and, due to the large lever arm of the lamp, to high torques, which can cause damage to the components and a loss of stability of the microscope.

The present invention aims to create a directly coupled, multichannel illuminating device that is free from the drawbacks of prior art solutions. In particular, the invention seeks to provide a multichannel illuminating device which is passively cooled without the use of fans and which exerts the lowest possible torque on the microscope.

We recognized that if the load-carrying element of the illuminating device is a heat sink having fins facing the microscope when the illuminating device is mounted, and the light sources are mounted on the back of the heat sink so that their light is guided to the microscope through an optical connector passing through the heat sink, then the cooling of the illuminating device can be provided by the heat sink itself, and the centre of gravity of the illuminating device can be brought as close as possible to the microscope. We also recognized that since the heat sink dissipates heat outwards through the fins towards the microscope, the back of the heat sink and the light sources etc. thereon can be enclosed in a sealed rear cover, thus preventing dust accumulation inside the illuminating device. It is also recognized that the above illuminating device can be manufactured more simply and at lower cost than state of the art directly coupled multichannel illuminating devices.

The problem according to the invention has been solved by using a directly coupled multichannel illuminating device according to claim 1 .

According to the invention, the illuminating device comprises a heat sink that functions as a load-bearing element, and the light sources are mounted on the back of the heat sink with heat conducting blocks inserted between them. The fins of the heat sink are arranged on the outside of the illuminating device, so that the heat generated by the light sources is conducted outwards through the heat sink in the direction of the fins and is dissipated on the surface of the fins to the outside. Another aspect of the invention is that the illuminating device is connected to the microscope by means of an optical connector passing through the heat sink and the light from the light sources is guided out of the illuminating device through the optical connector by means of an inclined mirror.

Some preferred embodiments of the invention are defined in the dependent claims.

Further details of the invention will be explained by means of embodiments and drawings. In the drawings:

Figure 1 is a schematic perspective view of an exemplary embodiment of an illuminating device according to the invention, viewed from the fins;

Figure 2 is a schematic front view of the illuminating device shown in Figure 1 ;

Figure 3a is a schematic perspective view of the illuminating device shown in Figure 1 , viewed from the back; Figure 3b is a schematic perspective view of the illuminating device shown in Figure 3a without the rear cover, viewed from the back;

Figure 4 is a schematic perspective view of another exemplary embodiment of the illuminating device according to the invention;

Figure 5 is a schematic perspective view of the illuminating device shown in Figure 1 when the illuminating device is mounted on a microscope;

Figure 6 is a schematic rear view of the illuminating device shown in Figure 1 with a transparent rear cover;

Figure 7 is a schematic rear view of an embodiment of an illuminating device according to the invention including a rotatable inclined mirror, shown without the rear cover.

Figure 1 shows a schematic perspective view of a directly coupled multichannel illuminating device 10 according to the invention. The illuminating device 10 is for producing electromagnetic output beams of different wavelengths, which can be particularly advantageously used for illuminating, for example, the slides of fluorescent microscopes 200. In the context of the present invention, the term beam is taken to include any collimated, focused or dispersed electromagnetic beam in the visible light or near visible light (e.g. infrared or ultraviolet) wavelength range, preferably having a circular cross-section, but also, for example, a square or rectangular cross-section. The illuminating device 10 has an imaginary optical axis 13 parallel to the direction of propagation of the output beams, indicated by the dashed line in Figure 1 . In other words, the optical axis 13 essentially coincides with the axes of symmetry of the output beams.

The illuminating device 10 according to the invention preferably comprises a heat sink 11 made of metal, preferably for example of aluminium or an aluminium alloy or other material having good thermal conductivity and providing sufficient structural strength. The heat sink 1 1 has a substantially flat back 1 1 a and is provided with fins 20 on a side 1 1 b opposite the back 1 1 a providing a large heat dissipating surface, as known to the person skilled in the art. In a possible embodiment, the heat sink 11 is square shaped as observed, for example, in Figure 2. The fins 20 are preferably formed from the material of the heat sink 11 . In a particularly preferred embodiment, the fins 20 are parallel plates configured such that the fins 20 are substantially vertical when the illuminating device 10 is mounted on the microscope 200 (see Figure 5). In this way, air heated by the heat dissipated by the fins 20 and rising due to convection can flow freely upward, further improving the heat dissipation of the heat sink 1 1 . The heat sink 1 1 acts as a load bearing element and is used to secure the components of the illuminating device 10.

The illuminating device 10 comprises a plurality of light sources 16 adapted to emit electromagnetic beams, which are connected to the back 1 1 a of the heat sink 1 1 by means of heat conducting blocks 17. For example, the embodiment shown in Figures 1 -3b comprises eight light sources 16, i.e. the illuminating device

10 in this case comprises eight channels. The heat conducting blocks 17 are elements made of a material with good thermal conductivity properties, preferably metal (e.g. aluminium), which connect the light sources 16 to the back 1 1 a and establish a conductive connection between them. In other words, the heat conducting blocks 17 conduct the heat generated by the light sources 16 to the back

11 a and transfer it to the heat sink 11 . It is noted that the heat conducting blocks 17 may be in direct contact with the back 1 1 a and the light sources 16, or, as may be possible, a thermally conductive material, such as a thermally conductive paste, may be applied between the contact surfaces, as will be apparent to the skilled person.

Each of the electromagnetic beams generated by the light sources 16 has a wavelength range, i.e. a spectral intensity distribution, specific to the light source 16 emitting it. The wavelength ranges of each beam are different (i.e. they cover different parts of the spectrum), but may also overlap. The light sources 16 are preferably chosen from a group of LEDs, lasers, laser-excited phosphors and laser- excited quantum dots. Note that “phosphor” in the context of the present description is understood to be the so-called photopowder known to the skilled person and not the chemical element in the periodic table, which does not necessarily contain phosphorus atoms. The phosphors used in the light sources 16 may be, for example, transition or rare earth metal compounds, such as oxides, silicates, sulfides, or halides.

The illuminating device 10 according to the invention comprises control electronics 30 connected to light sources 16 and adapted to operate the light sources 16. In a particularly preferred embodiment, the control electronics 30 are attached to the back 11 a of the heat sink 11 in a manner that allows heat transfer, as shown, for example, in Figure 3b. In this way, the heat generated by the control electronics 30 is transferred to the heat sink 1 1 through the back 1 1 a by heat conduction. Note that, for the sake of clarity, the electrical connections (e.g. wiring) between the control electronics 30 and the light sources 16 are not shown in the figures.

The illuminating device 10 further comprises an optical connector 40 attached to the heat sink 1 1 and extending through the heat sink 1 1 towards the side 1 1 b opposite the back 1 1 a, said optical connector 40 being formed as a light guide channel having a first end 40a facing the back 1 1 a and a second end 40b facing the microscope 200. By "light guide channel" in the context of the present invention, it is understood that the optical connector 40 is configured to transmit the output beam produced by the illuminating device 10. The optical connector 40 is for connecting the illuminating device 10 to the microscope 200 in such a way that the end 40b of the optical connector 40 extending from the fins 20 is attachable to a lamp inlet 210 of the microscope 200. The optical axis 13 of the device 10 passes through the optical connector 40 and preferably coincides with its longitudinal axis. The optical axis 13 is preferably perpendicular to the plane of the back 1 1 a. The optical connector 40 is secured to the heat sink 1 1 in a known manner, for example by screwing, soldering or gluing. The cross-section of the optical connector 40 may be, for example, circular or other, for example, rectangular, depending on the shape of the lamp inlet 210 of the microscope 200 (not shown in the figures). Optical elements, for example one or more optical lenses, may be arranged in the optical connector 40 between the ends 40a and 40b, for example, for focusing the output beam, as may be apparent to the person skilled in the art.

The illuminating device 10 according to the invention further comprises an inclined mirror 50 arranged on the back 1 1 a of the heat sink 1 1 , at the first end 40a of the optical connector 40 and for guiding the light of the light sources 16 through the optical connector 40 along the optical axis 13. The inclined mirror 50 deflects the beam from the respective light source 16 to its surface through the optical connector 40 along the optical axis 13 in the direction of the microscope 200. For example, the inclined mirror 50 may be fixed to the back 1 1 a by means of a spacer 51. In the exemplary embodiment shown in Figure 3b, optical elements 52 are arranged between the light sources 16 fixed to the back 1 1 a and the inclined mirror 50 to direct the light from the light sources 16 towards the inclined mirror 50. The optical elements 52 may be, for example, lenses and/or auxiliary mirrors, preferably dichroic mirrors, for focusing or deflecting the beams emitted by the light sources 16, as is known to the skilled person. The light sources 16 and the optical elements 52 are arranged such that the light from each of the light sources 16 reaches the surface of the inclined mirror 50, in such a way that the inclined mirror 50 deflects the beam incident thereon in the direction of the optical axis 13. Preferably, the beams emitted by the light sources 16 reach the inclined mirror 50 substantially parallel to the plane of the back 1 1 a, and the optical elements 52 are preferably fixed to the back 1 1 a, thus the power lever acting on the optical connector 40 is minimally increased.

In the possible embodiment shown in Figure 7, the inclined mirror 50 is configured to be rotatable about the optical axis 13 towards the respective light source 16. The rotation of the inclined mirror 50 may be performed manually or by means of a motor, preferably a stepping motor (not shown). In this embodiment, the light sources 16 are preferably arranged along a circular arc centred on the optical axis 13 and on the surface of the inclined mirror 50. That is, the electromagnetic beams emitted by the light sources 16 propagate parallel to the radii of the circular arc. To use a given light source 16, the inclined mirror 50 is rotated in the direction of the light source 16 so that the inclined mirror 50 deflects the beam incident thereon in the direction of the optical axis 13.

The illuminating device 10 according to the invention comprises a rear cover 60 arranged at the back 1 1 a of the heat sink 1 1 , connected to the heat sink 1 1 and defining an interior space 100 together with the back 1 1 a of the heat sink 1 1 . The rear cover 60 encloses the back 1 1 a and protects the components of the illuminating device 10 mounted on the back 1 1 a from external influences, as shown in Figure 3a. The cover 60 may be secured to the heatsink 1 1 in a manner known per se, for example by bolting, so that the cover 60 may be removed, if necessary, without damaging the illuminating device 10. In a particularly preferred embodiment, the interior space 100 bounded by the heat sink 11 and the rear cover 60 is closed. That is, there is no air flow between the interior space 100 and the outside, thereby protecting the light sources 16, control electronics 30 and, where applicable, optical elements 52 from dust and other contaminants. The closed interior space 100 is made possible by the fact that the heat generated by the light sources 16 and the control electronics 30 is conducted by the heat sink 11 , which dissipates to the environment through the fins 20. Thus, the heat generated is conducted in the direction of the fins 20, rather than towards the rear cover 60 or in lateral directions. The rear cover 60 may be made of, for example, plastic or other preferably lightweight material.

In a possible embodiment, the interior space 100 is divided into a first compartment 1 10 and a second compartment 120 by means of a partition wall 62, and the light sources 16 are arranged in the first compartment 1 10 and the control electronics 30 are arranged in the second compartment 120, as shown, for example, in Figure 6. In the figure, the wall 62 is indicated by a dashed line. Preferably, the compartments 110 and 120 are hermetically separated from each other by the wall 62. In a possible embodiment, the wall 62 is formed as part of the rear cover 60 from the material thereof. This can be easily achieved, for example in the case of a plastic cover 60, during the manufacture (e.g. injection moulding) of the cover 60. In this embodiment, the wall 62 is in contact with both the cover 60 and the back 1 1 a. In a preferred embodiment, the first compartment 110 is closed and the second compartment 120 is open to the outside. In the latter embodiment, the cover 60 preferably includes one or more vent openings 130 connecting the compartment 120 to the outside through which airflow between the compartment 120 and the outside may be provided. This has the advantage that some of the heat generated by the control electronics 30 can also escape through the vent 130, thereby providing more efficient cooling. It should be noted that dust may be able to enter the control electronics 30 through the vent 130, but as it is less sensitive to dirt, this is not a problem.

In a possible embodiment shown in Figure 4, the rear cover 60 is configured as a secondary heat sink 66 having a substantially flat secondary back and a side opposite to the secondary back provided with secondary fins 64, said secondary back facing the interior space 100, said secondary back being configured in contact with the heat conducting blocks 17 and preferably with the control electronics 30. In other words, in this embodiment, the heat sink 1 1 and the secondary heat sink 66 sandwich the heat conducting blocks 17 and preferably the control electronics 30, so that a portion of the heat generated by the illuminating device 10 is dissipated by the heat sink 66 and dissipated to the environment via its fins 64, thereby providing more efficient cooling. The secondary heat sink 66, like the heat sink 1 1 , can preferably be made of, for example, aluminium or aluminium alloy. Preferably, the fins 64 in the state of the illuminating device 10 mounted on the microscope 200 are also configured as substantially vertical parallel plates.

As the components of the illuminating device 10 (light sources 16, heat conducting blocks 17, control electronics 30, etc.) are fixed to the back 1 1 a, the centre of gravity of the illuminating device 10 is positioned as close as possible to the plane of the back 1 1 a of the heat sink 11 . In this way, the torque acting on the optical connector 40, and thus on the microscope 200, will be minimized.

Various modifications will be apparent to a person skilled in the art without departing from the scope of protection determined by the attached claims.

Claims

1 . A directly coupled multichannel illuminating device (10) for a microscope (200), characterized in that it comprises:

- a heatsink (11 ) having a substantially flat back (1 1 a) and provided with fins (20) on a side (1 1 b) opposite to the back (1 1 a),

- a plurality of light sources (16), each of which is connected to the back (1 1 a) of the heat sink (1 1 ) by means of heat conducting blocks (17),

- a control electronics (30) connected to the light sources (16) and adapted to operate the light sources (16),

- an optical connector (40) fixed to the heat sink (1 1 ) and extending through the heat sink (1 1 ) towards the side (1 1 b) opposite to the back (1 1 a), said optical connector (40) being formed as a light guide channel having a first end (40a) facing the back (1 1 a) and a second end (40b) facing the microscope (200),

- an inclined mirror (50) arranged at the first end (40a) of the optical connector (40) at the back (1 1 a) of the heat sink (1 1 ) and adapted to guide the light of the light sources (16) through the optical connector (40), and

- a rear cover (60) arranged at the back (1 1 a) of the heat sink (1 1 ), connected to the heat sink (1 1 ) and defining an interior space (100) together with the back (1 1 a) of the heat sink (1 1 ).

2. The illuminating device (10) according to claim 1 , characterized in that the fins (20) of the heat sink (1 1 ) are configured such that the fins (20) are substantially vertical when the illuminating device (10) is mounted on the microscope (200).

3. The illuminating device (10) according to claim 1 or 2, characterized in that the control electronics (30) are fixed to the back (1 1 a) of the heat sink (11 ).

4. The illuminating device (10) according to any one of claims 1 to 3, characterized in that the heat sink (11 ) is made of aluminium or aluminium alloy.

5. The illuminating device (10) according to any one of claims 1 to 4, characterized in that the interior space (100) bounded by the heat sink (11 ) and the rear cover (60) is closed.

6. The illuminating device (10) according to any one of claims 1 to 5, characterized in that the interior space (100) is divided into a first compartment (1 10) and a second compartment (120) by means of a partition wall (62), and the light sources (16) are arranged in the first compartment (1 10) and the control electronics (30) are arranged in the second compartment (120).

7. The illuminating device (10) according to claim 6, characterised in that the first compartment (1 10) is closed and the second compartment (120) is open to the outside.

8. The illuminating device (10) according to claim 6 or 7, characterised in that the partition wall (62) is formed as part of the rear cover (60).

9. The illuminating device (10) according to any one of claims 1 to 8, characterized in that the rear cover (60) is made of plastic.

10. The illuminating device (10) according to any one of claims 1 to 8, characterized in that the rear cover (60) is configured as a secondary heat sink (66) having a substantially flat secondary back and a side opposite to the secondary back provided with secondary fins (64), said secondary back facing the interior space (100), said secondary back being configured in contact with the heat conducting blocks (17) and preferably with the control electronics (30).

1 1. The illuminating device (10) according to any one of claims 1 to 10, characterized in that optical elements (52) are arranged between the light sources (16) and the inclined mirror (50) for directing the light from the light sources (16) towards the inclined mirror (50).

12. The illuminating device (10) according to any one of claims 1 to 1 1 , characterized in that the light sources (16) are selected from the group consisting of LEDs, lasers, laser-excited phosphors and laser-excited quantum dots.

13. The illuminating device (10) according to any one of claims 1 to 12, characterized in that the illuminating device (10) has an optical axis (13) passing through the optical connector (40), and the inclined mirror (50) is configured to be rotatable about the optical axis (13) towards the respective light source (16).