White-light source and intraocular illumination device

Abstract

The present invention relates to a white-light source and an intraocular illumination device comprising the white-light source. In particular, the invention relates to a white-light source for fiber-based intraocular illumination with light of a controllable, spectrally broad composition, and to an intraocular illumination device having corresponding controllability. A white-light source (100) according to the invention for fiber-based intraocular illumination with light of a controllable spectral composition comprises at least two light sources (10, 20, 30) for the provision of light beams of different colors, preferably with components substantially in the blue, green and red spectral range; wherein the individual light beams are combined to form a combined light beam (W); wherein the white-light source (100) is configured for individual control of the proportions of the individual light beams in the combined light beam (W); wherein at least one of the light sources (10, 20, 30) is a laser-activated remote phosphor, i.e. LARP, light source (90) with a phosphor as a conversion element (98) and a laser diode (92) for exciting the conversion element (98) by means of an excitation radiation (S) emitted by the laser diode (92).

Description

[0001] title

[0002] White light source and intraocular illumination device

[0003] Description

[0004] The present invention relates to a white light source and an intraocular illumination device comprising the white light source. In particular, the invention relates to a white light source for fiber-based intraocular illumination with light of a controllable, broad spectral composition, and to an intraocular illumination device with corresponding controllability.

[0005] State of the art

[0006] For intraocular illumination, for example during posterior segment surgery, light is delivered to the eye using light guides such as glass fibers or other fibers. In the context of the invention, the term "fiber" is used as a synonym for "light guide". These fibers have the smallest possible diameter and are inserted into the interior of the eye to be operated on. For this purpose, the fiber is inserted into the vitreous humor through a small incision at the edge of the eye. The distal end of the fiber can have a different shape depending on the respective illumination requirements (e.g. lensed fiber), so that the posterior segment of the eye can be illuminated either selectively or over a wide area, depending on the respective surgical requirements. Since the incision on the eye should be kept as small as possible, the permissible fiber diameters are limited.On the other hand, for optimal illumination of the surgical area, the highest possible light intensities should be delivered into the eye through the fiber. Therefore, the main goal of intraocular illumination devices is to deliver a high level of light to the eye using the smallest possible fiber diameter.

[0007] A further objective of such devices is to be able to adapt the spectral composition of the light to the respective application. This particularly concerns the tunability of the spectral composition of frequently required white light (adjustment of the color temperature). Corresponding light sources for providing light with an adjustable, spectrally broad composition essentially in the visible spectral range (VIS spectral range) are referred to as spectrally controllable white light sources. In the context of the invention, the terms "adjustable" and "adjustability" also particularly include "controllable" and "controllability". Furthermore, the light should also be capable of good color rendering. To achieve this, the lighting device should be capable of providing the largest possible color space with a spectrum that is as continuously covered as possible in the visible spectral range.An ophthalmologist often makes decisions based on subtle color nuances. These color nuances can only be observed and evaluated appropriately if the light used for illumination includes corresponding wavelengths. In particular, a natural reproduction close to the sunlight spectrum (or as it would appear through the respective surgical microscope) is preferred. A medical decision should, if possible, not be based on different lighting situations.

[0008] To date, xenon or halogen-based lamps have primarily been used as light sources. Light-emitting diodes (LEDs) are also used as an alternative. For lighting systems, so-called white light LEDs are used in particular. In these white light is usually generated by a phosphor that emits a broad spectrum when excited with blue light. And additive white light sources, in which the light emitted by red, green and blue LEDs is mixed to form white light. In both cases, a correspondingly low etendue of the emitted light limits the amount of light that can be coupled into the optical fiber. If the power density at and around the proximal end of the fiber is too high, the fibers can melt and be destroyed.When using phosphor-based white light LEDs, the color temperature of the emitted light cannot be controlled due to the predetermined conversion properties of the phosphor used, so that the emitted light must first be split into individual spectral components (e.g. via corresponding spectral filter elements) and then recombined according to the respective spectral requirements.

[0009] The use of laser diodes (LDs) instead of LEDs is also possible. Here, too, the light emitted by red, green, and blue LDs can be mixed to produce white light. However, due to their significantly reduced spectral bandwidth compared to corresponding LEDs, such white light only allows for very limited color rendering. The advantage of using LDs as light sources, however, lies in their very high etendue, which allows efficient coupling of the emitted light even into very small fiber diameters. Another disadvantage is the high coherence of the emitted radiation, which can lead to the formation of disruptive interference effects and the necessary compliance with laser safety standards. Additional diffusers or other elements that reduce the coherence of the radiation can reduce this, but lead to further losses and reduce the etendue.

[0010] There are now also LARP white light sources (Laser-Activated Remote Phosphor light sources), in which the conversion principle known from LEDs has been transferred to LDs. The radiation emitted by the LD is focused onto a phosphor as the conversion element, where it is converted into a corresponding white light spectrum and then collected again by the associated focusing optics. Due to the point excitation, the high etendue of the laser radiation is largely retained during the conversion process, but the high coherence of the excitation radiation is largely lost during the conversion process. With such LARP white light sources, it is possible to couple a significantly higher luminous intensity into fibers with diameters significantly smaller than 0.5 mm. In this respect, the known LARP white light sources generate largely coherence-free light with high etendue.However, LARP white light sources are not yet used for intraocular illumination purposes.

[0011] Disclosure of the invention

[0012] It is therefore an object of the present invention to provide a white light source and an intraocular illumination device which can provide light with particularly high etendue, low coherence and controllable, spectrally broad composition for fiber-based intraocular illumination.

[0013] These objects are achieved according to the invention by the features of independent patent claims 1 and 12. Advantageous embodiments of the invention are contained in the respective subclaims.

[0014] One aspect of the present invention relates to a white light source for fiber-based intraocular illumination with light of controllable spectral composition, comprising at least two light sources for providing light beams of different colors, preferably with components substantially in the blue, green, and red spectral range; wherein the individual light beams are combined into a common light beam; wherein the white light source is configured for individually controlling the proportion of the individual light beams in the common light beam; wherein at least one of the light sources is a laser-activated remote phosphor light source (LARP light source), with a phosphor as a conversion element and a laser diode for exciting the conversion element by means of excitation radiation emitted by the laser diode.

[0015] The white light source preferably comprises a light source for providing single-color light beams with respective components substantially in the blue, green, and red spectral ranges. The white light source preferably comprises a beam combiner for combining individual light beams into the common light beam.

[0016] In particular, the present invention relates to a white light source for fiber-based intraocular illumination with light of controllable spectral composition, comprising a light source for providing single-color light beams with respective components substantially in the blue, green, and red spectral range; and a beam combiner for combining the individual light beams into a common light beam; wherein the white light source is configured for individually controlling the proportion of the individual light beams in the common light beam; wherein at least one of the light sources is a laser-activated remote phosphor light source (LARP light source), with a phosphor as a conversion element and a laser diode for exciting the conversion element by means of excitation radiation emitted by the laser diode.

[0017] A white light source is a light source that is, at least in principle, suitable for providing white light with the broadest possible spectral distribution for the most complete color reproduction, and whose emitted white light spectrum thus results from a mixture of red, green, and blue spectral components. The spectral components can be characterized, in particular, as narrow-band separated regions (e.g., when using differently colored LDs) or by at least one contiguous spectral band (e.g., when using a white light LED or white light LARP). The adaptation of the overall white spectrum with regard to the intensities of the individual components or their spectral distribution is referred to as the controllability of the spectral composition.

[0018] A white light source according to the invention is therefore an RGB light source whose RGB composition can be selected as freely as possible. In particular, a white light source according to the invention should therefore also be designed to provide two-color or single-color light from only two or only one single light source by appropriately reducing and / or filtering one or more of the light sources included. A single light source can, for example, also be designed to emit two-color light, i.e., light of different colors with components essentially in two spectral ranges from the group of the blue, green, and red spectral ranges. However, a single light source for a combined provision of white light according to the invention preferably emits only single-color light due to the better controllability, i.e.Light of only a single color with components essentially in one spectral range from the group of blue, green and red spectral ranges.

[0019] The white light source according to the invention comprises a light source for providing monochromatic light beams with respective components essentially in the blue, green, and red spectral ranges. The term "monochromatic" refers to the respectively assigned spectral ranges of the light source, which result in particular from the color impression on an observer. In particular, the wavelength range from approximately 640 nm to approximately 780 nm is generally referred to as red, from approximately 490 nm to approximately 570 nm as green, and from approximately 430 nm to approximately 490 nm as blue. Corresponding transition ranges (e.g., greenish-blue, yellowish-green, yellowish-orange) are distinguished between these wavelength ranges. Since the human eye has receptors exclusively for light from these wavelength ranges, the entire range is also referred to as the visible spectral range (VIS spectral range).Below the blue spectral range are the violet (in the wavelength range from approximately 380 nm to approximately 430 nm) and the ultraviolet spectral range (UV spectral range, beginning in the wavelength range below approximately 380 nm). Above the red spectral range is the infrared spectral range (IR spectral range, beginning in the wavelength range above approximately 780 nm).

[0020] "Monochromatic light" within the meaning of the present invention is thus defined by the color impression and can encompass a relatively broad spectrum (from the respectively assigned spectral range) and thus even extend beyond the boundaries of the individual spectral ranges. Within the scope of the invention, monochromatic light can also be understood, for example, as light in the red-yellow, blue-green, or violet-blue spectral range. In contrast, the generally known technical term "monochromatic light" refers to light whose spectrum essentially encompasses only a single wavelength (or a very narrow range around a specific central wavelength). A laser diode with an emission wavelength of 680 nm emits essentially monochromatic light, whereas a red light-emitting diode, in contrast, emits spectrally relatively broad, monochromatic (but not monochromatic) red light with components essentially in the red spectral range.Depending on the spectral width of a light source, as described above, the individual light rays can also contain spectral components located far from the actual emission spectrum, outside the actual or immediately adjacent spectral ranges (e.g., excitation or primary light in converting light sources). Therefore, the respective components are also defined as essentially lying in the blue, green, and red spectral ranges. The respective color impression on an observer is particularly important here; however, a distinction can also be made based on the mutual intensity ratios of the individual spectral ranges of the emitted light.

[0021] The color impression can be quantitatively described by the so-called "dominant wavelength" of the corresponding light. The dominant wavelength of a light can be determined using the corresponding color space representation as the intersection point of the straight line defined from the white point through the color locus of the light source with the nearest edge of the color shoe. Narrow-edged or monofrequency light sources are located at the edge of the color shoe, while broadband light sources are located more centrally in the color shoe. The dominant wavelength defines the wavelength at which the emitted light is perceived as dominant by the human eye. Monochrome light rays with respective components, for example, primarily in the red spectral range, can thus be located near the red edge of the color shoe, with their dominant wavelength lying between approximately 640 nm and approximately 780 nm. The same applies to the other light colors.

[0022] The beam combiner can be an optical component or device for combining individual light beams into a single light beam. Such beam combiners can, for example, be designed as cube-shaped elements in which the input beams are coupled into the optical element via three different side surfaces and the combined beam is output at the corresponding fourth side surface (“X-Cube”). Corresponding beam combiners can also be provided entirely fiber-based (as so-called fiber combiners). Further embodiments of beam combiners are known from DE 10 2005 054 184 B4. Beam combiners are part of the state of the art and are therefore well known to those skilled in the art.

[0023] The white light source according to the invention is designed for individual control of the proportion of the individual light rays in the common light beam. This means that, for example, the intensity of the individual light sources can be individually controlled or the white light source according to the invention enables controllable attenuation of the individual light rays after they have been provided by the individual light sources. For this purpose, an electronic control can be provided for individually controllable the proportion of the individual light sources in the common light beam. In the simplest case, the control can directly relate to light generation in the individual light sources, for example, the control of an operating current to regulate the light intensity emitted by the individual light sources. However, the electronic control can also relate to optical control of the light intensity after the light rays have been provided.The individual control therefore concerns all means or measures suitable for varying the proportion of the individual light sources and is not limited to an individual type of intensity control.

[0024] According to the invention, at least one of the light sources is a LARP light source with a phosphor as a conversion element and a laser diode for exciting the conversion element using excitation radiation emitted by the laser diode. LARP light sources are part of the state of the art and are well known to those skilled in the art. Particularly preferably, all light sources of the white light source according to the invention are designed as LARP light sources.

[0025] The advantage of LARP light sources is their high etendue combined with high light intensities and low light coherence. This allows high power levels to be efficiently coupled into small fiber diameters without coupling losses causing an unacceptable temperature increase and thus melting of the proximal end of the fiber used for coupling. By using LARP light sources, at least the spectral component associated with these light sources can be coupled into a corresponding fiber with increased efficiency compared to the light from other light sources. By using LARP light sources exclusively in a white light source according to the invention, the maximum light intensity that can be coupled into a corresponding fiber can be significantly increased compared to other white light sources in the prior art.

[0026] According to the invention, three LARP light sources with individual spectra in the colors red, green, and blue are preferably mixed. The respective spectra are kept rather narrowband compared to the overall spectrum of a typical white-light LED, but are significantly broader than a mixed RGB laser arrangement. In particular, very broad red, green, and blue spectral components can be generated in this way in order to mix them and control them individually. The higher spectral bandwidths of LARP light sources also make it possible to achieve good to very good color rendering. By distributing the power components across three light sources, higher power levels are also possible than when using conventional white-light LEDs.In contrast to direct white light emitters with a continuous broadband spectrum, the individual provision of the color components also allows a targeted, reduced overall spectrum to be created, thereby improving the ratio of light quantity to bandwidth. The components of the individual light beams can be regulated or controlled to a specific color location via an electronic control system. In particular, the individual disadvantages of previous technologies can be supplemented or compensated for by the advantages of the other technologies. LARP technology eliminates disadvantages caused by typical laser properties such as high coherence lengths, laser speckle, poor color rendering, and the otherwise necessary classification into laser classes.

[0027] The conversion element preferably comprises an auxiliary phosphor for adapting the conversion element to the excitation radiation of the laser diode. Depending on the LD used to excite certain phosphors as a conversion element, it may be advantageous to include a so-called auxiliary phosphor in the phosphor composition or to use it within the corresponding assembly. Any excitation radiation from an exciting LD that may not be spectrally optimally designed can be adapted to the specific absorption properties of the phosphor used with the desired target spectrum. The auxiliary phosphor can thus be used to adapt the excitation radiation. However, the conversion element can preferably also comprise multiple phosphors to define a specific converted color spectrum. This can, in particular, increase the bandwidth of the conversion light.The individual phosphors can be mixed together during production so that they are distributed as evenly as possible within the conversion element. For example, the spectral distribution of a LARP light source emitting in the red, green, or blue spectral range can be specifically adapted to the required lighting requirements by the phosphor mixture used in the conversion element.

[0028] Preferably, the at least one LARP light source is designed to emit white light. Adaptation of the spectral bandwidth or spectral profile of the emitted white light to provide the associated monochrome light beam can be achieved by a spectral filter element between the corresponding LARP light source and the beam combiner, or as an element of the beam combiner. This means that the broad spectral distribution of the emitted light of a white-light LARP is reduced or modified by an additional spectral filter element. The spectral distribution behind the spectral filter element then results, for example, as the product of the spectral distribution of the white-light LARP with the spectral profile of the passband of the spectral filter element. Within the scope of the invention, it is preferred that the passband be provided multiple times, in particular twice.Additionally, within the scope of the invention, for example for regulatory and / or legislative reasons, an additional filter can be arranged in the common light beam or in the blue light beam to protect the eye, which can further reduce the proportion of blue light reaching the eye. This makes it possible to increase the duration of a surgical procedure.

[0029] The spectrum of a white-light LARP is typically very broad and enables very good color reproduction even after spectral filtering. A disadvantage of this arrangement, however, is that the filtering means only a fraction of the original light intensity is available for coupling into an optical fiber, since part of the white light is filtered out at the spectral filter element. The spectral filter element can also be integrated directly into the housing of a LARP light source (monochrome LARP light source). The spectral filter element can also be designed as an element of the beam combiner, for example, as a dielectric filter layer applied directly to the surface of the beam combiner or an internal interface of the beam combiner. The beam combiner preferably mixes spectrally in such a way that losses are minimized and the input powers are summed.

[0030] Preferably, the at least one LARP light source is designed to directly provide the associated colored light beam. Preferably, the associated colored light beam is directly provided by a customized combination of phosphor and laser diode within the at least one LARP light source. In contrast to the embodiment described in the previous paragraph with an additional spectral filter element, a LARP light source that already emits a single color is used here. This can be achieved, in particular, by the phosphor of the conversion element converting the corresponding excitation radiation only into a very specific spectral range. A variety of temperature-resistant phosphors are available for the different spectral ranges.However, the spectral distribution of a LARP light source designed specifically to provide the corresponding colored light beam can be further adjusted using a spectral filter element. In this case, the intensity loss at the spectral filter element can be significantly reduced compared to a monochromatically filtered white-light LARP.

[0031] The colored light beam with components essentially in the blue spectral range is preferably provided via a light-emitting diode (LED) or laser diode (LD) that emits essentially in the blue or violet spectral range. The colored light beams with components essentially in the red and green spectral ranges are preferably provided by means of a LARP light source each. This configuration is preferred because the blue or violet spectral range is only required to a small extent for color mixing and can therefore be implemented directly via an LED, for example. In this way, the construction costs for a white light source according to the invention can be reduced, in particular, because LEDs and LDs are significantly cheaper than corresponding LARP light sources and replacing them in the blue spectral range does not result in any significant disadvantages.

[0032] Preferably, the colored light beam with components essentially in the blue spectral range is provided via a laser diode emitting light essentially in the blue or violet spectral range. Additionally, the laser diode can be used to excite a conversion element for providing a single-color light beam with components essentially in the cyan spectral range (LARP light source in the cyan spectral range).

[0033] The use of monochromatic light in the cyan spectral range, for example, enables direct stimulation of fluorescein fluorescence in the eye and / or can be used to achieve improved color rendering. The cyan spectral range is not uniformly defined in the prior art, but is generally assigned to the wavelength range from 482 nm to 494 nm, particularly between 487 nm and 492 nm. The cyan spectral range is thus spectrally located at the low-energy edge of the blue spectral range, or very close to the green spectral range.

[0034] Since light in the blue spectral range has higher energy than light in the green spectral range, the cyan spectral range can be provided, in particular, by converting blue or violet light using phosphors ("cyan phosphor"). Since, as already stated above, the blue spectral range is usually only required to a small extent for color mixing, a portion of the generated blue laser radiation can be used to create a LARP light source that provides a single-color light beam with components primarily in the cyan spectral range. The light beams with components primarily in the blue spectral range and the cyan spectral range can share a common light path toward the beam combiner.The white light source according to the invention can thus be designed in particular such that a higher amount of blue or violet light is initially generated internally than is needed for a specific, predetermined correlated color temperature (CCT). This amount can then be converted using a cyan phosphor to obtain a white light or filtered colored light with precisely defined properties.

[0035] The white light source according to the invention preferably further comprises a LARP light source as a light source for providing a monochromatic light beam with components substantially in the cyan spectral range, wherein the individual light beams are combined into a common light beam via the beam combiner, wherein the individual light beams have separate light paths. Except for the independence of the light source for providing monochromatic light beams with components substantially in the blue spectral range, this embodiment essentially corresponds to the embodiment described in the previous paragraph; the explanations there therefore apply accordingly. The associated beam combiner must be able to combine four monochromatic light beams on separate light paths into a common light beam.

[0036] The white light source according to the invention preferably further comprises a sensor for monitoring the at least one LARP light source (error sensor, in particular a break sensor). Since the phosphors used in the conversion element are exposed to high thermal stresses, overloading can lead to fractures and disruptions in the structure of the phosphor. This can cause the intensity of the emitted light to drop significantly, making it advisable to divert the corresponding test light for continuous or repeated monitoring of the light output.

[0037] However, it is also possible that the laser radiation used to excite the conversion element is inadvertently reflected and directly coupled into the illumination device. Since blue laser radiation in particular, even at low power levels, can have a highly damaging effect on biological tissue structures and cells, particularly on the retina and optic nerve in the eye, it is necessary to immediately shut down the illumination device or the excitation laser, or at least block the damaging radiation components. This can also be achieved by appropriate power monitoring in all light beams and / or by evaluating the spectral properties of the provided light beams. If, for example, a sharp increase in the spectral range of an excitation beam is detected, an appropriate response can be made automatically.

[0038] The sensor can thus be designed in particular to monitor the intensity of the high-energy blue or violet components in the provided spectrum. If a sudden, strong increase in intensity is registered for these components, then at least a safety shutdown of the excitation of the corresponding LARP light source or a complete shutdown of the corresponding LARP light source or of the entire white light source according to the invention can occur. Alternatively, the ratio of the intensity of the provided white light (or the total intensity in the case of a single- or multi-colored light that deviates from white light through appropriate control of the white light source according to the invention) to the blue spectral component can be measured and monitored. The sensor can be arranged at a suitable location in the beam path of the white light source according to the invention.

[0039] A further aspect of the present invention relates to an intraocular illumination device comprising a white light source according to the invention, an optical fiber for intraocular illumination and a fiber coupling (optical system) for coupling the common light beam into a proximal end of the optical fiber.

[0040] Preferably, the optical fiber has an active diameter of less than or equal to 0.1 mm and can emit a luminous flux of greater than 1 lm at its distal end.

[0041] The light output required for intraocular illumination devices is between approximately 1 lm and 40 lm. This depends on the respective situation, the tools used, and the specific eye condition of the patient. With conventional LED light sources, a maximum of approximately 20 lm can be introduced into 23G fibers with an active diameter of 0.486 mm and an NA of 0.5. Linearly scaled down, this means that with conventional LED light sources, a maximum of approximately 0.85 lm can be introduced into a corresponding fiber with an active diameter of 0.1 mm and the same NA. Using a white light source according to the invention, this value can be significantly increased due to the high etendue of the at least one LARP light source.With the preferred active diameters of the fibers between about 0.05 mm and 0.1 mm, at least 1 μm, preferably between 2 μm and 3 μm and even more preferably up to 30 μm can be coupled into the respective fibers.

[0042] Further preferred embodiments of the invention emerge from the features recited in the respective subclaims. The various embodiments of the invention recited in this application can be advantageously combined with one another, unless otherwise stated in individual cases.

[0043] Brief description of the drawings

[0044] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show:

[0045] Fig. 1 is an exemplary schematic representation of a fiber-coupled LARP light source according to the prior art,

[0046] Fig. 2 is an exemplary schematic representation of a first embodiment of a white light source according to the invention with three independent light sources,

[0047] Fig. 3 is an exemplary schematic representation of a LARP light source for providing two single-color light beams,

[0048] Fig. 4 is an exemplary schematic representation of a second embodiment of a white light source according to the invention with four independent light sources,

[0049] Fig. 5 an intraocular illumination device according to the invention,

[0050] Fig. 6 a typical spectrum of a white light LED, and

[0051] Fig. 7 a typical spectrum of a white light LARP.

[0052] Detailed description of the drawings

[0053] Figure 1 shows an exemplary schematic representation of a fiber-coupled LARP light source 90 according to the prior art. The excitation radiation S emitted by a laser diode 92 (excitation laser) is deflected, for example, via a dichroic mirror 94 and focused onto a correspondingly adapted conversion element 98 by means of focusing optics 96. Phosphor is used as the conversion element 98 in a LARP light source 90. The phosphor is typically arranged on a substrate or carrier designed as a heat sink. The conversion light L emitted by the excited conversion element 98 at the focus of the focusing optics 96 is then confocally collected and collimated by the focusing optics 96. After passing through the dichroic mirror 94, the conversion light L can be coupled into a light guide 120, for example, an optical fiber, via a corresponding fiber coupling 110.A corresponding LARP light source 90 can be individually constructed from individual components or purchased as a fully integrated unit. The LARP light source 90 shown represents only one possible variant for constructing such a light source; numerous other construction variants are well known to those skilled in the art.

[0054] Figure 2 shows an exemplary schematic representation of a first embodiment of a white light source 100 according to the invention with three independent light sources 10, 20, 30. The white light source 100 shown for fiber-based intraocular illumination with light of controllable spectral composition comprises a light source 10, 20, 30 for providing single-color light beams R, G, B with respective components essentially in the blue, green, and red spectral ranges; and a beam combiner 50 (so-called X-Cube) for combining the individual light beams R, G, B into a common light beam W; wherein the white light source 100 is configured for individually controlling the proportion of the individual light beams R, G, B in the common light beam W. wherein one of the light sources 20 is a laser-activated remote phosphor light source, LARP light source, 90 with a phosphor as a conversion element (cf. conversion element 98 in Fig. 1) and a laser diode (cf.Laser diode 92 in Fig. 1) for exciting the conversion element (see above) by means of an excitation radiation emitted by the laser diode (see above) (cf. excitation radiation S in Fig. 1).

[0055] In particular, the LARP light source 90 shown can be configured to emit white light (white light LARP), and a spectral filter element 22 between the corresponding LARP light source 90 and the beam combiner 50 can adjust the spectral bandwidth of the emitted white light to provide the associated monochrome green light beam G. The spectral filter element 22 can also be configured as an element of the beam combiner 50, for example, as a dielectric filter layer applied directly to the surface of the beam combiner 50 or an inner interface of the beam combiner 50. Preferably, the beam combiner 50 mixes spectral components in such a way that losses are minimized and the input powers are summed.

[0056] According to the invention, however, the at least one LARP light source 90 can also be configured to directly provide the associated colored light beam (in this case, the green light beam G). In particular, the associated colored light beam G can be directly provided by an adapted combination of phosphor and laser diode within the at least one LARP light source 90.

[0057] Furthermore, an optional additional sensor 60 for monitoring the at least one LARP light source 90 is shown in the beam path. This sensor can, for example, divert a portion of the combined light beam W to a detector configured to monitor the intensity in a specific spectral range. If a sudden increase in light intensity is detected, the white light source 100 according to the invention can be regulated down or controlled accordingly to protect the user or patient (error sensor, in particular a breakage sensor for monitoring the conversion element). In the case of open-loop control, a specific value can be set for the light intensity to be provided. In the case of closed-loop control, the system behavior can be determined at specific times and controlled accordingly. The sensor can be arranged at a suitable location in the beam path of the white light source according to the invention.

[0058] Figure 3 shows an exemplary schematic representation of a LARP light source for providing two single-color light beams. The basic structure of the LARP light source 90 corresponds to the embodiment shown in Fig. 1; the individual reference numerals and their assignments therefore apply accordingly. In the illustration, the colored light beam B with components essentially in the blue spectral range is provided via a laser diode 92 that emits light essentially in the blue spectral range. The laser diode 92 also excites a conversion element 98 to provide a single-color light beam C with components essentially in the cyan spectral range.The dichroic mirror 94 can be designed as a beam splitter, so that a portion of the blue excitation light B is reflected by a reflector 32 arranged behind it and can be superimposed at the dichroic beam splitter 98 with the generated conversion light of the monochromatic light beam C with components essentially in the cyan spectral range. Such a light source could, for example, be used in the embodiment of a white light source 100 shown in Fig. 2 as a third light source 30 for providing two monochromatic light beams (B, C) with respective components essentially in the blue spectral range B and in the cyan spectral range C.

[0059] In an alternative embodiment of a LARP light source for providing two single-color light beams (e.g., cyan and blue), a particularly compact uniaxial beam path can be realized without an additional beam splitter by using a transparent conversion element (e.g., a cyan phosphor). For example, the light from a blue LARP light source (or a white-light LARP with a high blue component) can be used directly to excite a corresponding transparent conversion element. Through excitation, a portion of the transmitted blue light is then converted into cyan light, resulting in an overlay of blue and cyan components behind the conversion element.

[0060] Figure 4 shows an exemplary schematic representation of a second embodiment of a white light source 100 according to the invention with four independent light sources. In addition to the embodiment shown in Fig. 2, the white light source 100 further comprises a LARP light source (for example according to Fig. 1) as light source 40 for providing a monochrome light beam C with components essentially in the cyan spectral range, wherein the individual light beams R, G, B, C are combined into a common light beam W via the beam combiner 50, wherein the individual light beams R, G, B, C have separate light paths. The beam combiner 50 shown is, by way of example, a sequence of individual beam combiners in which two input beams on separate light paths are combined into a common light path.

[0061] Figure 5 shows an intraocular illumination device 200 according to the invention. The intraocular illumination device 200 shown comprises a white light source 100 according to the invention; a light guide 120 for intraocular illumination; and a fiber coupling 110 (optical system) for coupling the common light beam W into a proximal end of the light guide 120. Preferably, the light guide 120 is designed as an optical fiber, wherein the optical fiber has an active diameter of less than 0.1 mm and can emit a luminous flux of greater than 1 lm at its distal end.

[0062] Figure 6 shows a typical spectrum of a white-light LED. For example, a red, green, and blue light-emitting diode can be combined as so-called RGB LEDs in a common LED housing, emitting a spectrum that appears white. For better color rendering with a broader spectral range, a portion of the light from a so-called primary LED can also be shifted into a different spectral range using a conversion element. Depending on the phosphor, such conversion spectra can extend over a spectral width of up to several hundred nm. High-energy blue or ultraviolet light from a corresponding LED is usually used as the excitation light for the conversion.

[0063] In the spectrum shown, clear peaks can be seen at approximately 460 nm (blue) and approximately 630 nm (red). The green-yellow spectral range between approximately 597 nm and approximately 580 nm, in contrast, exhibits the typical flat curve of a phosphor's conversion spectrum. The resulting white light spectrum is highly modulated and exhibits clearly visible dips in intensity, particularly at the individual range transitions (around approximately 480 nm and approximately 600 nm). By attenuating the individual peaks, a more uniform spectrum can be achieved, but this significantly reduces the total intensity available for radiation.

[0064] Fig. 7, in contrast, shows a typical spectrum of a commercial white-light LARP. A blue excitation laser emitting at 450 nm was used to excite the conversion element. The excitation spectrum is significantly narrower than that of LEDs (the spectral width shown is limited by the spectrometer used). By effectively exciting the conversion element, a broad conversion spectrum between approximately 470 nm and approximately 700 nm can be generated. The spectrum exhibits a flat profile, very similar to the solar spectrum, without any discernible modulation. Such a spectral profile, due to its wide color gamut, enables significantly improved color rendering compared to the light from white-light LEDs or RGB LEDs. Furthermore, the spectrally non-overlapping excitation light can be filtered out using a suitable low-pass filter without affecting the conversion spectrum.

[0065] Additionally, the figure shows, by way of example, the filter function of a bandpass filter operating in the green spectral range between approximately 497 nm and approximately 530 nm, such as could be used as a spectral filter element 22 in a light source 20 for providing a monochromatic light beam G with components essentially in the green spectral range in a white light source 100 according to the invention (cf. Fig. 2). However, bandpass filters with significantly wider filter bandwidths can also be used. For an extended green spectral range, for example, a spectral filter element with a passband between approximately 497 nm (green) and approximately 575 nm (greenish-yellow) can be provided.

[0066] List of reference symbols

[0067] 10 first light source (red)

[0068] 20 second light source (green)

[0069] 22 spectral filter element

[0070] 30 third light source (blue)

[0071] 32 reflector

[0072] 40 fourth light source (cyan)

[0073] 50 beam combiners

[0074] 60 Sensor (e.g. error or breakage sensor)

[0075] 90 LARP light source

[0076] 92 Laser Diode (LD)

[0077] 94 dichroic mirrors

[0078] 96 Focusing optics

[0079] 98 conversion element (e.g. phosphorus(s))

[0080] 100 white light source

[0081] 110 Fiber coupling

[0082] 120 light guides

[0083] 200 intraocular illumination device

[0084] S Excitation radiation

[0085] L Conversion light (e.g. monochrome, white or hyperspectral)

[0086] R first light beam (red)

[0087] G second light beam (green)

[0088] B third light beam (blue)

[0089] C fourth light beam (cyan)

[0090] W combined light beam (white)

Claims

Patent claims 1. A white light source (100) for fiber-based intraocular illumination with light of controllable spectral composition, comprising: at least two light sources (10, 20, 30) for providing light beams of different colors, preferably with components substantially in the blue, green, and red spectral ranges, wherein the red spectral range extends between wavelengths of about 640 nm to about 780 nm, the green spectral range between wavelengths of about 490 nm to about 570 nm, and the blue spectral range between wavelengths of about 430 nm to about 490 nm; wherein the individual light beams are combined into a common light beam (W); wherein the white light source (100) is configured for individually controlling the proportion of the individual light beams in the common light beam (W);wherein at least one of the light sources (10, 20, 30) is a laser-activated remote phosphor light source, LARP light source, (90) with a phosphor as a conversion element (98) and a laser diode (92) for exciting the conversion element (98) by means of an excitation radiation (S) emitted by the laser diode (92).

2. White light source (100) according to claim 1, wherein the white light source (100) comprises a light source (10, 20, 30) for providing monochromatic light beams (R, G, B) with respective components substantially in the blue, green and red spectral range.

3. White light source (100) according to claim 1 or 2, wherein the white light source (100) comprises a beam combiner (50) for combining individual light beams into the common light beam (W).

4. White light source (100) according to one of claims 1 to 3, wherein the conversion element (98) comprises an auxiliary phosphor for adapting the conversion element (98) to the excitation radiation (S) of the laser diode (92) and / or the conversion- The element (98) comprises several phosphors for defining a converted color spectrum. A white light source (100) according to any one of claims 1 to 4, wherein the at least one LARP light source (90) is configured to emit white light. A white light source (100) according to claim 5, wherein a spectral filter element (22) between the LARP light source (90) configured to emit white light and the beam combiner (50), or a spectral filter element (22) as an element of the beam combiner (50), adjusts the spectral profile of the emitted white light to provide the corresponding light beam. A white light source (100) according to any one of claims 1 to 4, wherein the at least one LARP light source (90) is configured directly to provide the colored light beam (R, G, B).A white light source (100) according to claim 7, wherein the colored light beam (R, G, B) is provided directly by a matched combination of phosphor and laser diode (92) within the at least one LARP light source (90). A white light source (100) according to any one of claims 2 to 8, wherein the colored light beam (B) with components substantially in the blue spectral range is provided by a diode or laser diode (92) emitting light substantially in the blue or violet spectral range, and the colored light beams (R, G) with components substantially in the red and green spectral ranges are provided by means of separate LARP light sources (90), wherein the violet spectral range extends between wavelengths of about 380 nm to less than about 430 nm, and the blue spectral range at least partially comprises a cyan spectral range extending between wavelengths of about 482 nm to about 494 nm.White light source (100) according to one of claims 2 to 9, wherein the provision of the colored light beam (B) with components substantially in the blue or violet spectral range is carried out via a laser diode (92) emitting light substantially in the blue or violet spectral range and via the laser diode. (92) additionally, an excitation of a conversion element (98) is carried out to provide a monochromatic light beam (C) with components essentially in the cyan spectral range, wherein the violet spectral range extends between wavelengths of about 380 nm to about less than 400 nm and the cyan spectral range extends between wavelengths of about 482 nm to 494 nm. White light source (100) according to one of claims 2 to 9, further comprising a LARP light source (90) as a light source (40) for providing a monochromatic light beam (C) with components substantially in the cyan spectral range, wherein the individual light beams (R, G, B, C) are combined into a common light beam (W) via the beam combiner (50), wherein the individual light beams (R, G, B, C) have separate light paths, and wherein the cyan spectral range extends between wavelengths of about 482 nm to about 494 nm.Intraocular illumination device (200), comprising: a white light source (100) according to any one of the preceding claims; an optical fiber (120) for intraocular illumination; and an optical fiber coupling (110) for coupling the common light beam (W) into a proximal end of the optical fiber (120). Intraocular illumination device according to claim 12, wherein the optical fiber (120) is configured as an optical fiber, the optical fiber having an active diameter of less than 0.1 mm and being able to emit a luminous flux greater than 1 Im at its distal end.

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