Optical light guide device and method for operating an optical light guide device

Abstract

The invention relates to a light guide device (100) for guiding light. The light guide device (100) comprises a light excitation element (117) having at least one first excitation element (116) and one second excitation element (124). The first excitation element (116) can be excited by a first light (114) having a first wavelength (300). As an alternative, the first light (114) can be output by the first excitation element (116). The second excitation element (124) can be excited by a second light (122) having a second wavelength (302) which differs from the first wavelength (300). As an alternative, the second light (122) can be output by the second excitation element (124). The optical light guide device (100) also comprises a waveguide (108) for guiding the first light (114) and second light (122). The waveguide (108) comprises a first holographic element (110) for forming a first light path (112) for the first light (114) through the first excitation element (116). Furthermore, the waveguide (108) comprises a second holographic element (118) for forming a second light path (120), which differs from the first light path (112), for the second light (122) through the second excitation element (124). The waveguide (108) has at least one section (206) comprising the first light path (112) and the second light path (120).

Description

[0001] Description

[0002] Title and procedure for operating a

[0003] State of the art

[0004] The invention relates to an optical light guide device and a method for operating an optical light guide device according to the preamble of the independent claims. The present invention also relates to a control unit, a computer program, and a machine-readable storage medium.

[0005] One way to generate radiation with different color or wavelength bands is to excite various phosphors with characteristic emission spectra. Application examples include fluorescence-based methods in medical technology or RGB projectors. In the associated optical system, it may be crucial that the phosphor switching unit ensures or enables defined properties for the input and output beams. These defined properties can include the position, direction, and divergence of the beams. Abstractly, the switching unit can be divided into a demultiplexer, which distributes the radiation across the different optical paths with phosphors, and a multiplexer, which recombines the different optical paths.

[0006] Different phosphor-coated bodies can be used as exchange units, which, when mechanically moved, can introduce one of the phosphors into the beam path at a time. Effectively, in this example, there is only one optical path in which an element can be mechanically exchanged. As a second implementation option, a mechanical mirror can be used that can select a static phosphor array depending on its inclination (demultiplexing). The multiplexing process can also be performed by the mechanical mirror, which can redirect the phosphor's fluorescence radiation back towards the excitation radiation. A wavelength-selective optical element, for example, a dichroic mirror, can separate the excitation radiation and the fluorescence radiation.

[0007] Disclosure of the invention

[0008] Against this background, the approach presented here comprises a method, a control unit that uses this method, and finally a corresponding computer program according to the main claims. The measures listed in the dependent claims enable advantageous further developments and improvements of the optical light guide device specified in the independent claim.

[0009] An optical light-guiding device is presented, comprising a light excitation element with at least one first excitation element and one second excitation element. The first excitation element can be excited by a first light with a first wavelength, or the first light can be emitted through the first excitation element. The second excitation element can be excited by a second light with a second wavelength different from the first, or the second light can be emitted through the second excitation element. The optical light-guiding device further comprises a waveguide for guiding the first light and the second light. The waveguide includes a first holographic element for forming a first light path for the first light through the first excitation element.The waveguide further comprises a second holographic element for forming a second light path, distinct from the first, for the second light passing through the second excitation element. The waveguide has at least one section encompassing both the first and second light paths. A light-guiding device can be understood here as a device for guiding light, which includes a light excitation element, i.e., an element that can be excited by the action or illumination of light. For this purpose, the light excitation element comprises a first excitation element, i.e., an element that can be excited by a first light. This first light has a first wavelength and thus excites the excitation element. The light-guiding device also comprises a second excitation element, i.e., an element that can be excited by a second light.This second light has a different wavelength and thus excites the excitation element. The wavelength of the second light differs from the wavelength of the first light.

[0010] The optical fiber assembly also includes a waveguide by means of which the first and second lights can be guided into or along the optical fiber assembly. To guide the first light through or onto the first excitation element via a first light path, the waveguide includes a first holographic element. This can generally be understood as an optical element whose operating principle is based on holography. A holographic element can deflect a specific light radiation, characterized by a wavelength, from one direction of propagation, characterized by a wavefront and direction, to another direction of propagation, specifically characterized by a different wavefront and direction.

[0011] The approach presented here is based on the understanding that a light excitation element arranged in or on an optical light guide device can be excited by different lights or light sources with different wavelengths (colors) and / or luminous intensities using holographic elements. The wavelength of the light (both from the laser and the phosphor) can also determine the position at which the light is coupled out of the waveguide and thus which phosphor it strikes (in the case of laser radiation), as well as the point at which the radiation is coupled into the waveguide (in the case of radiation from the phosphor). This function is particularly advantageous because the light guide device can thus be used, for example, for fluorescence-based investigations, methods, or analyses in medical technology, but also, for instance, in an RGB projector, LED projector, or other type of projector.It can be used with a built-in laser projector.

[0012] According to one embodiment, the first holographic element and the second holographic element can be arranged on the same side of the waveguide. This proves advantageous because the light guide device can be manufactured easily.

[0013] According to a further embodiment, the first holographic element and the second holographic element can be arranged on a side of the waveguide opposite the light excitation element or on the same side of the light excitation element. In particular, the first holographic element and the second holographic element can be arranged on a carrier separate from the waveguide. This offers the advantage of a compact design for the light guide device, results in a higher degree of flexibility, and can facilitate the fabrication of the holographic elements. Specifically, if the first and / or second holographic element is designed as a transparent holographic element, an arrangement on the same side of the light excitation element can be advantageous.

[0014] According to a further embodiment, the light excitation element can comprise a first light-shaping element, for example a first lens, associated with the first excitation element, and / or a second light-shaping element, for example a second lens, associated with the second excitation element. In particular, the first light-shaping element can be arranged between the first excitation element and the first holographic element. Alternatively or additionally, the second light-shaping element can be arranged between the second excitation element and the second holographic element. Alternatively, the first light-shaping element can be arranged on a side of the first excitation element opposite the first holographic element, and / or the second light-shaping element can be arranged on a side of the second excitation element opposite the second holographic element.The light shaping elements and the holographic elements concentrate the lights onto the excitation elements. The light shaping elements optionally have different refractive indices for this purpose.

[0015] According to a further embodiment, the first excitation element and / or the second excitation element can comprise at least one luminophore and / or one fluorophore. This enables favorable illumination behavior of the light guide device, especially when the first light and / or the second light is switched off.

[0016] According to another embodiment, the waveguide can be disc-shaped and / or cylindrical. The compact design achieved by this embodiment enables a defined emission pattern of the light guide device.

[0017] According to a further embodiment, the light excitation element can have a third excitation element. This third excitation element can be excited by a third light with a wavelength different from both the first and second wavelengths. Alternatively, the third light can be output through the third excitation element. The waveguide can be configured to guide the third light. Furthermore, the waveguide can have a third holographic element to form a third light path for the third light through the third excitation element, different from both the first and second light paths. The waveguide can have at least one section encompassing the first light path, the second light path, and the third light path. Such an embodiment thus offers the possibility of exciting the light excitation element with a third light.

[0018] According to a further embodiment, the first holographic element and / or the second holographic element can be arranged on a first film. This allows for easy application of the holographic elements to the waveguide and simplifies the fabrication of the light guide device. According to a further embodiment, the first holographic element and / or the second holographic element can comprise a plurality of sub-elements. This enables reliable and advantageous formation of the light paths for the lights through the excitation elements.

[0019] According to a further embodiment, the optical light guide device can have a further waveguide for guiding the first light and the second light. This further waveguide can have a further first holographic element in the first light path for the first light passing through the first excitation element and a further second holographic element in the second light path for the second light passing through the second excitation element. The further waveguide can have at least one section encompassing both the first and second light paths. In particular, the light excitation element can be arranged between the waveguide and the further waveguide. Such an embodiment allows for further possibilities and combinations of light excitation using the light guide device.

[0020] According to a further embodiment, the optical light guide device can include a controllable light source for outputting the first light and / or the second light into the waveguide and / or into the light excitation element. Using the controllable light source, the lights can be output into the waveguide and / or into the light excitation element individually, according to customer requirements.

[0021] According to a further embodiment, the controllable light source can comprise a laser light source, in particular a laser diode, wherein the light source can be controlled such that the wavelength emitted by the light source is variable. This adjustment can be based on various effects. One possibility is the targeted exploitation of the temperature dependence of semiconductor components, which influences the peak wavelength of the emission spectrum, thus enabling, for example, targeted control of this temperature for modulating the wavelength of light emitted by the light source. This embodiment enables targeted, variable, and controllable light output from the laser light source.

[0022] Also presented is a method for operating an optical light guide device. The method comprises a step of illuminating a first light into a first path of a waveguide to excite a first excitation element. Additionally or alternatively, in the same step, a second light is irradiated into a second path of the waveguide to excite a second excitation element.

[0023] This process can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, such as in a control unit.

[0024] The presented approach also creates a control unit designed to execute and / or control the step of the aforementioned procedure or a similar procedure within a corresponding unit. This implementation of the presented approach, in the form of a control unit, also allows the underlying problem to be solved quickly and efficiently.

[0025] For this purpose, the control unit can have at least one processing unit for processing signals or data, at least one storage unit for storing signals or data, at least one interface to a sensor or actuator for reading sensor signals from the sensor or for outputting control signals to the actuator, and / or at least one communication interface for reading or outputting data embedded in a communication protocol. The processing unit can be, for example, a signal processor, a microcontroller, or the like, and the storage unit can be flash memory or a magnetic storage device.The communication interface can be configured to read or output data wirelessly and / or via wired connections, whereby a communication interface that can read or output wired data can, for example, read this data electrically or optically from or output it into a corresponding data transmission line.

[0026] In this context, a control unit can be understood as an electrical device that processes sensor signals and outputs control and / or data signals accordingly. The control unit can have an interface, which may be implemented in hardware and / or software. In the case of a hardware-based interface, the interfaces can, for example, be part of a so-called system ASIC, which incorporates various functions of the control unit. However, it is also possible that the interfaces are separate integrated circuits or at least partially comprised of discrete components. In the case of a software-based interface, the interfaces can be software modules, which, for example, are located on a microcontroller alongside other software modules.

[0027] Also advantageous is a computer program product or computer program with program code that can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out, implement and / or control the steps of the method according to one of the embodiments described above, in particular if the program product or program is executed on a computer or device.

[0028] Furthermore, the presented approach creates a machine-readable storage medium on which the aforementioned computer program or a similar computer program can be stored.

[0029] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows:

[0030] Fig. 1 is a block diagram of an optical light guide device according to an embodiment; Fig. 2 is a schematic representation of an optical light guide device according to an embodiment;

[0031] Fig. 3 shows a schematic representation of an optical light guide device according to an exemplary embodiment;

[0032] Fig. 4 shows a schematic representation of an optical light guide device according to an exemplary embodiment;

[0033] Fig. 5 shows a schematic representation of an optical light guide device according to an exemplary embodiment;

[0034] Fig. 6 shows a schematic representation of an optical light guide device according to an exemplary embodiment;

[0035] Fig. 7 shows a diagram of a laser diode for use in an optical light guide device according to an exemplary embodiment;

[0036] Fig. 8 shows a flowchart of an embodiment of a method for operating an optical light guide device; and

[0037] Fig. 9 shows a schematic representation of a control unit for carrying out a method for operating an optical light guide device as described above.

[0038] In the following description of favorable embodiments of the present approach, the same or similar reference numerals are used for the elements shown in the various figures and which have a similar effect, without repeating these elements.

[0039] Fig. 1 shows a block diagram of an optical light guide 100 according to an exemplary embodiment. A controllable light source 102, for example a laser light source 104, in particular a laser diode, emits light 106 with a specific wavelength 107 into a waveguide 108. According to one exemplary embodiment, the waveguide 108 guides radiation based on total internal reflection at the interfaces. For total internal reflection to occur, it may be a requirement that, firstly, the refractive index of the waveguide 108 is greater than that of its surroundings, and, alternatively or additionally, that an angle of incidence (to the normal) greater than the smallest angle for total internal reflection is maintained. The smallest angle for total internal reflection is given by Snell's law of refraction.For example, for all angles of incidence smaller than the smallest angle for total internal reflection, the radiation is refracted at the interface of a surrounding area of ​​the waveguide 108 and coupled out of the waveguide 108.

[0040] The waveguide 108 comprises a first holographic element 110, which forms a first light path 112 for a first light 114, optionally by means of a first light-shaping element 115, by means of a first excitation element 116 of a light-excitation element 117. The first excitation element 116 optionally comprises a luminophore. Alternatively or additionally, the first excitation element 116 comprises a fluorophore. Preferably, holograms are incorporated into photothermorefractive (PTR) glass. Due to the greater thickness of PTR glass compared to other materials into which holograms are written, thicker holograms can be realized. Thicker holograms result in a sharper spectrum, which allows for a smaller delta between the wavelengths of the first, second, and nth light and leads to a better spectral filtering effect.

[0041] The waveguide 108 also includes a second holographic element 118, which forms a second light path 120 for a second light 122, distinct from the first light path 112, optionally by means of a second light-shaping element 123, by means of a second excitation element 124 of the light-excitation element 117. The second excitation element 124 optionally includes a luminophore. Alternatively or additionally, the second excitation element 124 includes a fluorophore.

[0042] The waveguide 108 also includes a third holographic element 126, which forms a third light path 128 for a third light 130, distinct from the first light path 112 and the second light path 120, optionally by means of a third light-shaping element 131, or by means of a third excitation element 132 of the light-excitation element 117. The third excitation element 132 optionally includes a luminophore. Alternatively or additionally, the third excitation element 132 includes a fluorophore.

[0043] The first light 114 is transmitted in the first light path 112, optionally also via a first collimation optic 134, to another first holographic element 136 of another waveguide 138. The second light 122 is transmitted in the second light path 120, optionally also via a second collimation optic 140, to another second holographic element 142 of the other waveguide 138. The third light 130 is transmitted in the third light path 128, optionally also via a third collimation optic 144, to another third holographic element 146 of the other waveguide 138.

[0044] In other words, the controllable light source 102, for example the laser light source 110, in particular the laser diode, emits a laser, laser beam or light beam, i.e. the light 106, which has a wavelength 107, in particular a variable wavelength, to a holographic demultiplexer, i.e. to the waveguide 108. A tunable laser is a laser whose emission wavelength can be controlled. A demultiplexer is a component that can route a single input to one of several outputs, depending on a control signal.

[0045] The demultiplexer sends the laser, laser beam, light 106, or light beam, optionally via focusing optics (i.e., via the light-shaping elements 115, 123, 131), to a phosphor fluorescent or a phosphor fluorescent, i.e., to the light excitation element 117. The light excitation element can be referred to as a phosphor, luminescent pigment, or phosphor. The laser, laser beam, or light beam (i.e., the light 106 emitted by the phosphor) is then transmitted, optionally via the collimation optics 134, 140, 144, to a holographic multiplexer (i.e., to the further waveguide 138). A multiplexer is a component that can, depending on a control signal, connect one of several inputs to one output.According to one embodiment, this figure 1 can also be described as a visualization of the phosphor changer, i.e. the phosphor changer, i.e. the light guide device 100, as a block diagram consisting of the demultiplexer, i.e. the waveguide 108, and the multiplexer, i.e. the further waveguide 138.

[0046] The approach presented can only be divided, by way of example, into the functionality of a demultiplexer and that of a multiplexer. Excitation radiation of different wavelengths is split by a demultiplexer into N different optical paths, i.e., light paths 112, 120, 128. Phosphor conversion takes place in each of the optical paths, i.e., light paths 112, 120, 128. The fluorescence of each path, i.e., each light path 112, 120, 128, is combined, for example, by a multiplexer. Figure 1 shows a corresponding block diagram.

[0047] The disclosed approach implements, by way of example, a phosphor changer, abstractly expressed and by way of example, a demultiplexer, i.e. the waveguide 108, for the excitation radiation and a multiplexer for the fluorescence radiation, between whose outputs and inputs phosphors can be excited.

[0048] A phosphor changer, in this context, refers to a device that allows one of several phosphors to be variably excited within an optical system and its fluorescence to be utilized. A control variable can determine which optical path, i.e., which light path 112, 120, 128, is selected with the phosphor.

[0049] According to the embodiment illustrated in Figure 1, the presented approach implements both the demultiplexer, i.e., waveguide 108, and the multiplexer, i.e., the additional waveguide 138, which is based on different wavelengths of the radiation as a control signal. The control signal for the demultiplexer is the wavelength of the excitation radiation. The control signal for the multiplexer is the wavelength of the fluorescence radiation. Selection is achieved, for example, via holographic optical elements 110, 118, 126, which can couple radiation out of one of the waveguides 108, 138 and couple it into the other. The demultiplexer consists, for example, of a light source whose wavelength can be varied, such as a tunable laser. This laser is coupled into a waveguide, i.e., waveguide 108, on the side of which HOEs 110, 118, 126 are attached.Each of these HOEs 110, 118, 126 modifies at least the direction of the radiation of a specific wavelength coupled into the waveguide such that the critical angle for total internal reflection is exceeded and the radiation is coupled out of the waveguide 108. Each HOE 110, 118, 126 is active for a different wavelength, so the selection of the HOE 110, 118, 126 that couples out the radiation is determined by the wavelength of the radiation coupled into the waveguide. Preferably, the HOE 110, 118, 126 couples out the radiation perpendicular to the propagation direction of the waveguide. The number of HOEs 110, 118, 126 corresponds to the number of outputs of the demultiplexer.

[0050] Each output of the demultiplexer is connected to a phosphor. The use of additional focusing elements, i.e., the light-shaping elements 115, 123, 131, for the excitation radiation and, additionally or alternatively, the use of collimating elements, i.e., the collimation optics 134, 140, 144, for the fluorescence radiation is conceivable.

[0051] A holographic optical element 110, 118, 126, or HOE for short, can deflect a specific light radiation, characterized by the wavelength 107, from one direction of propagation, characterized by wavefront and direction, into another, thus acting, for example, as a focusing or defocusing element.

[0052] HOEs 110, 118, and 126 can be based on diffraction and interference, which may be wavelength-dependent. This wavelength dependence can result in the optical function of the holograms being effective only for a small wavelength range. For radiation outside the wavelength range that interacts with the structure in HOE 110, 118, and 126, volume holograms, in particular, can be nearly transparent. Thus, HOEs 110, 118, and 126 can have a spectral filtering effect. A superposition of HOEs 110, 118, and 126, each designed for a specific wavelength, can make it possible to optically influence radiation of different wavelengths in different ways.

[0053] Between the demultiplexer and the multiplexer, as already indicated in the block diagram in Figure 1, further optical elements, such as the light-shaping elements 115, 123, 131, can be placed in the beam path. Before the radiation strikes the phosphor, i.e., the light excitation element 117, a focusing lens, i.e., one of the light-shaping elements 115, 123, 131, can be used to reduce the size of the spot on the phosphor. In the case of a reflective arrangement, the fluorescent radiation can be collimated, for example, by such a lens, i.e., one of the light-shaping elements 115, 123, 131, or, in the case of a transmittive arrangement, by another lens, i.e., one of the collimation optics 134, 140, 144.

[0054] Instead of introducing further optical elements in the form of lenses, i.e., in the form of the light-shaping elements 115, 123, 131 or the collimation optics 134, 140, 144, a focusing or parallelizing effect can be added to the HOEs in addition to changing the direction. Thus, it is possible to have the HOE that couples the radiation out of the waveguide 108, 138 focus the radiation directly onto the phosphor, and conversely, to collimate the fluorescent radiation that is coupled from the phosphor into the waveguide 108, 138 with an HOE.

[0055] Fig. 2 shows a schematic representation of an optical light guide device 100 according to an exemplary embodiment. The controllable light source 102, for example the laser light source 104, in particular the laser diode, emits the light 106 with the specific wavelength 107, which corresponds to A0, into the waveguide 108, which is optionally designed in a disk-shaped or cylindrical shape.

[0056] The waveguide 108 comprises the first holographic element 110, which optionally has a first plurality of sub-elements 200 and forms the first light path 112 for the first light 114. The waveguide 108 also comprises the second holographic element 118, which optionally has a second plurality of sub-elements 202, but does not form a light path in this Figure 2. The waveguide 108 also comprises the third holographic element 126, which optionally has a third plurality of sub-elements 204, but also does not form a light path in this Figure 2.

[0057] The waveguide 108 includes a section 206 comprising the first light path 112.

[0058] The first holographic element 110, the second holographic element 118 and the third holographic element 126 are each optionally arranged on a first foil 208 and optionally on an equal side 210 of the waveguide 108.

[0059] The controllable light source 212, for example a laser light source 214, in particular a laser diode, emits further light 216 with a specific further wavelength 218, which corresponds to Xo + AX ​​1, into the waveguide 138, which is optionally designed in a disc-shaped or cylindrical shape.

[0060] The further waveguide 138 comprises the further first holographic element 136, which optionally has a further first plurality of sub-elements 220, but does not form a light path in this Figure 2. The further waveguide 138 also comprises the further second holographic element 142, which optionally has a further second plurality of sub-elements 222 and forms the second light path 120, which is distinct from the first light path 112. The further waveguide 138 also comprises the further third holographic element 146, which optionally has a further third plurality of sub-elements 224, but also does not form a light path in this Figure 2.

[0061] The further waveguide 138 includes a further section 226 comprising the second light path 120.

[0062] The further first holographic element 136, the further second holographic element 142 and the further third holographic element 146 are each optionally arranged on a further film 228 and optionally each on a further identical side 230 of the further waveguide 138

[0063] An additional controllable light source 232, for example an additional laser light source 234, in particular an additional laser diode, emits an additional light 236 with a certain additional wavelength 238, which corresponds to Ao + AA 2, into an additional waveguide 240 which is optionally designed in a disk shape or a cylindrical shape.

[0064] The additional waveguide 240 comprises an additional first holographic element 242, which optionally has an additional first plurality of sub-elements 244, but does not form a light path in this Figure 2. The additional waveguide 240 also comprises an additional second holographic element 246, which optionally has an additional second plurality of sub-elements 248, but also does not form a light path in this Figure 2. The additional waveguide 240 also comprises an additional third holographic element 250, which optionally has an additional third plurality of sub-elements 252 and forms the third light path 128, which is distinct from the first light path 112 and the second light path 120.

[0065] The additional waveguide 240 includes an additional section 254 comprising the third light path 128.

[0066] The additional first holographic element 242, the additional second holographic element 246 and the additional third holographic element 250 are each optionally arranged on a third sheet 256 and optionally on an additional identical side 258 of the additional waveguide 240.

[0067] According to one embodiment, Figure 2 can also be described as a possible realization of the demultiplexer, i.e., the waveguide 108, the further waveguide 138, or the additional waveguide 240, for three outputs: the first light path 112, the second light path 120, and the third light path 128. Figure 2 shows the demultiplexer three times by way of example, each with one of the wavelengths 107, 218, 238 corresponding to the HOEs, i.e., the holographic optical elements or holographic elements 110, 118, 126, 136, 142, 146, 242, 246, 250.

[0068] Fig. 3 shows a schematic representation of an optical light guide device 100 according to an exemplary embodiment. The controllable light source 102, for example the laser light source 104, in particular the laser diode, emits the light 106 with the defined wavelength 107 into the waveguide 108, which is optionally designed in a disk-shaped or cylindrical shape.

[0069] The first holographic element 110, the second holographic element 118 and the third holographic element 126 are arranged on a side 300 of the waveguide 108 opposite the light excitation element 117.

[0070] The further first holographic element 136, the further second holographic element 142 and the further third holographic element 146 are arranged by way of example on a further side 302 of the further waveguide 138 opposite the light excitation element 117.

[0071] For example, the first light-shaping element 134 is arranged between the first excitation element 116 and the second holographic element 136. Similarly, for example, the second light-shaping element 140 is arranged between the second excitation element 124 and the second holographic element 142. Also for example, the third light-shaping element 144 is arranged between the third excitation element 132 and the third holographic element 146.

[0072] By means of the first light-shaping element 115 (not shown in Fig. 3) and the first holographic element 110, the first light 114 is concentrated onto the first excitation element 116. By means of the second light-shaping element 123 (not shown in Fig. 3) and the second holographic element 118, the second light 122 is concentrated onto the second excitation element 124. By means of the third light-shaping element 131 (not shown in Fig. 3) and the third holographic element 126, the third light 130 is concentrated onto the third excitation element 132. The light-shaping elements 115, 123, and 131 optionally have different refractive indices for this purpose. By means of the first light shaping element 134, the light 114 is directed from the excitation element 116 to the further first holographic element 136. By means of the second light shaping element 140, the second light 122 is directed from the second excitation element 124 to the further second holographic element 142.By means of the third light shaping element 144, the third light 130 is directed onto the further third holographic element 146. The light shaping elements 134, 140, 144 optionally have different refractive indices for this purpose.

[0073] The first excitation element 116 is excited by the first light 114 with a first wavelength 304. The second excitation element 124 is excited by the second light 122 with a second wavelength 306, which differs from the first wavelength 304. The third excitation element 132 is excited by the third light 130 with a third wavelength 308, which differs from both the first wavelength 304 and the second wavelength 306.

[0074] According to one embodiment, Figure 3 can also be described as a possible realization of the demultiplexer, i.e., the waveguide 108, and the multiplexer, i.e., the further waveguide 138, in two different components for three paths with phosphors, i.e., for three light paths 112, 120, 128. As an example, the demultiplexer is shown on the left, the phosphors, i.e., the excitation elements 116, 124, 132 (also called phosphors), in the middle, an optic, i.e., the light-shaping elements 134, 140, 144, is also shown in the middle, and the multiplexer is shown on the right. In this Figure 3, all paths, i.e., all light paths 112, 120, 128, are shown simultaneously as an example.

[0075] Demultiplexers and multiplexers can be implemented in two separate components, as shown in Fig. 3. Transmissive phosphor excitation is a suitable option for using two components.

[0076] It is therefore possible to use both functions, the multiplexer and the demultiplexer, individually. In particular, the multiplexer function can be used by exciting the phosphors separately. Excitation can be achieved, for example, by a laser directed onto the phosphors via a mechanical mirror, or by using a separate laser for each phosphor.

[0077] This design variant can alternatively be described as using the multiplexer and demultiplexer individually or as a design variant in two (different) components.

[0078] Fig. 4 shows a schematic representation of an optical light guide device 100 according to an exemplary embodiment. The controllable light source 102, for example the laser light source 104, in particular the laser diode, emits the light 106 with the defined wavelength 107 into the waveguide 108, which is optionally designed in a disk-shaped or cylindrical shape.

[0079] The waveguide 108 comprises the first holographic element 110, which optionally has the first plurality of sub-elements 200 and forms the first light path 112 for the first light 114. For this purpose, the waveguide 108 includes the section 206 comprising the first light path 112. The waveguide 108 also comprises the second holographic element 118, which optionally has the second plurality of sub-elements 202, but does not form a light path in this Figure 2. The waveguide 108 also comprises the third holographic element 126, which optionally has the third plurality of sub-elements 204, but also does not form a light path in this Figure 2.

[0080] The first holographic element 110, the second holographic element 118 and the third holographic element 126 are each optionally arranged on the first slide 208 and optionally on the same side 210 of the waveguide 108.

[0081] For example, the first light-shaping element 115 is arranged between the first excitation element 116 and the first holographic element 110. Also for example, the second light-shaping element 123 is arranged between the second excitation element 124 and the second holographic element 118. And again for example, the third light-shaping element 131 is arranged between the third excitation element 132 and the third holographic element 126.

[0082] The first excitation element 116 is excited by the first light 114 with the first wavelength 304. By means of the first light-shaping element 115 and the first holographic element 110, the first light 114 is focused onto the first excitation element 116. By means of the first light-shaping element 115, which in the reflective use of the excitation element 116 assumes the function of the optional light-shaping element 134, and the first holographic element 110, which in the reflective use of the excitation element 116 assumes the function of the further first holographic element 136, the light 114 is coupled into the waveguide 108 collimated by the excitation element 116 at a wavelength that differs from the wavelength 304 of the light 114 from the light source 102.

[0083] According to one embodiment, this Figure 4 can also be described as additional optical elements in the individual paths or as a possible realization of the demultiplexer, i.e., the waveguide 108, and the multiplexer, i.e., the further waveguide 138, in a component for three paths with phosphors, i.e., for three light paths. In this Figure 4, only the first path, i.e., the first light path 112, is active by way of example.

[0084] Demultiplexing and multiplexing can also be combined in a single component. To transform the demultiplexer into a multiplexer, the HOE functions are doubled by using HOEs that have different optical functions for two wavelength intervals. One function couples the excitation light out of the waveguide 108, 138, and another function couples the fluorescence light back into the waveguide 108, 138 at a longer wavelength. Figure 4 shows the combination of a demultiplexer and a multiplexer in one component. A reflective arrangement of the phosphors is recommended for combining the two functions in one component.

[0085] Fig. 5 shows a schematic representation of an optical light guide device 100 according to an exemplary embodiment. The controllable light source 102, for example the laser light source 104, in particular the laser diode, emits the light 106 with the defined wavelength 107 into the waveguide 108, which is optionally designed in a disk-shaped or cylindrical shape.

[0086] The waveguide 108 comprises the first holographic element 110, which optionally has the first plurality of sub-elements 200 and forms the first light path 112 for the first light 114. The waveguide 108 also comprises the second holographic element 118, which optionally has the second plurality of sub-elements 202 and forms the second light path 120 for the second light 122. The waveguide 108 also comprises the third holographic element 126, which optionally has the third plurality of sub-elements 204 and forms the third light path 128 for the third light 130.

[0087] The first holographic element 110, the second holographic element 118 and the third holographic element 126 are each optionally arranged on the first slide 208 and optionally on the same side 210 of the waveguide 108.

[0088] The first excitation element 116, located opposite the first holographic element 110, is excited by the first light 114. The second excitation element 124, located opposite the second holographic element 118, is excited by the second light 122. The third excitation element 132, located opposite the third holographic element 126, is excited by the third light 130.

[0089] According to one embodiment, this figure 5 can also be described as an embodiment with phosphors directly on the waveguide, or as an embodiment in a component, or as a realization of both functions, i.e., demultiplexing and multiplexing, with phosphors attached directly to the waveguide, i.e., to the waveguide 108, i.e., the excitation elements 116, 124, 132.

[0090] In order to minimize the installation space and to excite the phosphor, i.e. the excitation elements 116, 124, 132, and capture the fluorescence radiation as efficiently as possible, i.e. with little distance, using the HO Es 110, 118, 126, the excitation elements 116, 124, 132 can be attached directly to the waveguide 108.

[0091] Preferably, in this case, the HOEs 110, 118, 126 have a focusing function for the laser radiation and therefore additionally assume the function of the optional and here obsolete light-shaping elements 115, 123, 131. Preferably, in this case, the HOEs 110, 118, 126 have a collimating function for the radiation from the phosphor and therefore additionally assume the function of the optional and here obsolete light-shaping elements 115, 123, 131 or 134, 140, 144.

[0092] However, care should be taken to ensure that the guided modes, i.e., in this case the wavelengths 107, do not hit the phosphors in the waveguide 108, since the angle for total reflection is smaller due to the higher refractive index of the phosphors.

[0093] Fig. 6 shows a schematic representation of an optical light guide device 100 according to an exemplary embodiment.

[0094] The further waveguide 138 comprises the further first holographic element 136, which optionally has the further first plurality of sub-elements 220 and forms the first light path 112. The further waveguide 138 also comprises the further second holographic element 142, which optionally has the further second plurality of sub-elements 222 and forms the second light path 120, which is different from the first light path 112. The further waveguide 138 also comprises the further third holographic element 146, which optionally has the further third plurality of sub-elements 224 and forms the third light path 128, which is different from the first light path 112 and the second light path 120.

[0095] The further first holographic element 136, the further second holographic element 142, and the further third holographic element 146 are each optionally arranged on the further sheet 228 and optionally on the further same side 230 of the further waveguide 138. The further sheet 228 can also be called PTG, be a PTG sheet, or have PTG.

[0096] For example, the first light-shaping element 134 is arranged between the first excitation element 116 and the second holographic element 136. Similarly, for example, the second light-shaping element 140 is arranged between the second excitation element 124 and the second holographic element 142. Also for example, the third light-shaping element 144 is arranged between the third excitation element 132 and the third holographic element 146.

[0097] By means of the first light-shaping element 134 and the further first holographic element 136, the first light 114 from the first excitation element 116 is coupled into the further waveguide 138. By means of the second light-shaping element 140 and the further second holographic element 142, the second light 12 from the second excitation element 124 is coupled into the further waveguide 138. By means of the third light-shaping element 144 and the further third holographic element 146, the third light 130 from the third excitation element 132 is coupled into the further waveguide 138. The light-shaping elements 134, 140, and 144 optionally have different refractive indices for this purpose.

[0098] The first excitation element 116 is excited by the first light 114 with the first wavelength 304. The second excitation element 124 is excited by the second light 122 with the second wavelength 306, which differs from the first wavelength 304. The third excitation element 132 is excited by the third light 130 with the third wavelength 308, which differs from both the first wavelength 304 and the second wavelength 306. The excitation elements 116, 124, and 132 can also be referred to as phosphors.

[0099] According to one embodiment, Figure 6 can also be described as a possible realization of the multiplexer, i.e., the additional waveguide 138, for three inputs. In this Figure 6, all inputs couple in simultaneously by way of example. According to such an embodiment, it is important to ensure that the HOEs, i.e., the additional holographic elements 136, 142, 146, are arranged and the functions of the HOEs are selected such that the waves guided in the additional waveguide 138, i.e., the light paths 112, 120, 128, are superimposed. Due to the wavelength selectivity, i.e., the selectivity of the HOEs for wavelengths 304, 306, 308, a combination of the guided waves according to this embodiment is expected to be practically feasible.

[0100] Due to the wavelength selectivity of the HOE, demultiplexers and multiplexers exhibit a spectral filtering effect, as the optical function of the HOE is expected to be active only at and around its design wavelength. This filtering function can be particularly helpful when multiplexing the fluorescence of phosphors, allowing for the expansion of the color gamut in visual RGB applications and the narrowing of the excitation spectrum in fluorescence-based investigations. The design wavelength of the HOE can be chosen to match the desired spectral range of the radiation, rather than necessarily coinciding with the maximum emission of the phosphor.

[0101] Alternatively, such a design variant can be described as the wavelength selectivity of the HOEs.

[0102] The multiplexer consists of an additional waveguide 138 with the same number of HOEs 136, 142, 146 on one side. The optical function of the HOEs 136, 142, 146 is to couple the incident fluorescence radiation into the additional waveguide 138 by deflecting the radiation so that it has an angle of incidence to the interface between the additional waveguide 138 and its surroundings that is greater than or equal to the minimum angle for total internal reflection. The HOEs 136, 142, 146 are each optimized for the wavelength interval to be realized, matching the phosphor. The arrangement combines the fluorescence radiation from the phosphors in the additional waveguide 138, which can then be processed by the next optical system at the end of the additional waveguide 138. Figure 6 shows an exemplary embodiment of the optical multiplexer with three inputs.Depending on the specific design, HOEs can be used either reflectively, as shown in the preceding figures, or transmittively. Accordingly, such designs can be referred to as transmittive or reflective HOEs. Reflective HOEs couple the radiation in and out through the waveguide. In transmittive HOEs, the coupling out and in occurs on the side of the HOE. Transmittive HOEs are therefore located on the side of the waveguide facing the excitation element (phosphor) 116. The transmittive variant has the advantage that the HOE is closer to the phosphor, thus allowing for better focusing or collimation.

[0103] Fig. 7 shows a diagram 700 of a laser diode for use in an optical light guide device according to an exemplary embodiment. Wavelengths A are shown on the abscissa 702. pea k of a laser diode and a temperature-dependent shifted wavelength A peak + AA is plotted. An optical power P is plotted on the ordinate 704. op t [au] is plotted in a range from zero (0) to one (1). All waves reach the optical power P. op t = T0 of One (1).

[0104] According to one embodiment, this figure 7 can also be described as the spectrum of a laser diode at temperatures between 25 degrees Celsius (°C) and 70 degrees Celsius (°C) or as the change in laser wavelength due to temperature.

[0105] Unlike a tunable laser, where the emission wavelength can be intentionally changed, a change in emission wavelength with temperature can be an unwanted side effect. Conventionally, the temperature of a laser diode can be controlled using a Peltier element. Figure 7 shows exemplary spectra of a laser at different temperatures.

[0106] According to one embodiment, the wavelength of the excitation radiation is considered the control signal, and a tunable laser is used as an example of a light source with a narrow spectrum and an adjustable wavelength. An alternative to the tunable laser is a temperature-controlled laser. As can be seen by way of example in Fig. 7, the peak wavelength of a diode laser according to one embodiment varies in the temperature range between 25 degrees Celsius and

[0107] A temperature change of 75 degrees Celsius results in a drift of approximately 3 nanometers. This drift can be exploited by designing the HOEs in the demultiplexer, for example, to operate within a narrow wavelength range. To then switch the output, the laser can be heated or cooled, resulting in a different peak wavelength and thus activating a different output. Since it is expected that temperature is not the only factor influencing the peak wavelength of the laser spectrum, it is also advisable to consider and ideally utilize other influencing factors, such as current.

[0108] Alternatively, such a design variant can be described as a variation of the control signal for the demultiplexer.

[0109] Since the phosphors in question have a broad absorption spectrum, small changes in wavelength, such as those occurring during temperature fluctuations, have a negligible effect on the excitation of the phosphor. Furthermore, a phosphor can always be excited at the same wavelength, thus ensuring reproducible results.

[0110] Conversely, phosphor combinations requiring different excitation wavelengths are also conceivable. The present approach could be particularly suitable for such phosphor combinations.

[0111] Alternatively, such a design variant can be described as a discussion of the variable excitation wavelength of the phosphors.

[0112] Fig. 8 shows a flowchart of an embodiment of a method 800 for operating an optical light guide device. The method comprises a step 805 of shining first light into a first path of a waveguide to excite a first excitation element. Additionally or alternatively, in step 805 of the shining process, a second light is shining into a second path of the waveguide to excite a second excitation element. Fig. 9 shows a schematic representation of a control unit 900 for carrying out a method as described above for operating an optical light guide device or a similar method. The control unit 900 comprises a shining unit 905 for shining first light into a first path of a waveguide to excite a first excitation element.Additionally or alternatively, a second light is directed into a second path of the waveguide using the single-beam unit 905 to excite a second excitation element.

[0113] If an embodiment includes an “and / or” connection between a first feature and a second feature, this is to be read as meaning that the embodiment according to one embodiment has both the first feature and the second feature, and according to another embodiment either only the first feature or only the second feature.

[0114] According to one embodiment, the disclosed approach can also be referred to as a holographic phosphor changer.

[0115] Advantages compared to known light guide devices include the fact that the approach presented here, for example, does not require moving parts, offers miniaturization potential, can combine the functionality of demultiplexing and multiplexing in one component or divide it into two different components according to an exemplary embodiment, performs spectral filtering in particular through the use of HOEs 110, 118, 126, and can potentially be manufactured cost-effectively in larger quantities.

[0116] For fluorescence-based investigations such as PCR analyses, the use of phosphors to create different excitation channels is already known. The present approach demonstrates a clever way to implement phosphor switching. Besides its use in fluorescence-based methods such as in medical technology, its application in RGB projectors is also conceivable.

Claims

Claims 1. Optical light guide device (100) with the following features: - a light excitation element (117) with at least one first excitation element (116) and a second excitation element (124), wherein the first excitation element (116) can be excited by a first light (114) with a first wavelength (300) or the first light (114) can be output through the first excitation element (116), and wherein the second excitation element (124) can be excited by a second light (122) with a second wavelength (302) different from the first wavelength (300) or the second light (122) can be output through the second excitation element (124); and - a waveguide (108) for guiding the first light (114) and the second light (122), wherein the waveguide (108) has a first holographic element (110) for forming a first light path (112) for the first light (114) from or to the first excitation element (116) and a second holographic element (118) for forming a second light path (120) for the second light (122) from or to the second excitation element (124), different from the first light path (112), wherein the waveguide (108) has at least one section (206) encompassing the first light path (112) partially and the second light path (120) partially 2. Optical light guide device (100) according to claim 1, wherein the first holographic element (110) and the second holographic element (118) are arranged on the same side of the waveguide (108).

3. Optical light guide device (100) according to one of the preceding claims, wherein the first holographic element (110) and the second holographic element (118) are arranged on a side (300) of the waveguide (108) opposite the light excitation element (117) or on the same side of the light excitation element (117), in particular wherein the first holographic element (110) and the second holographic element (118) are arranged on a support separate from the waveguide (108).

4. Optical light guide device (100) according to one of the preceding claims, wherein the light excitation element (117) comprises a first light shaping element (115) associated with the first excitation element (116) and / or a second light shaping element (123) associated with the second excitation element (124), in particular wherein the first light shaping element (115) is arranged between the first excitation element (116) and the first holographic element (110) and / or the second light shaping element (123) is arranged between the second excitation element (14) and the second holographic element (118), or wherein the first light shaping element (115) is arranged on a side of the first excitation element (116) opposite the first holographic element (110) and / or the second light shaping element (123) is arranged on a side of the second excitation element (124) opposite the second holographic element (118).

5. Optical light guide device (100) according to one of the preceding claims, wherein the first excitation element (116) and / or the second excitation element (124) comprises at least one luminophore and / or one fluorophore.

6. Optical light guide device (100) according to one of the preceding claims, wherein the waveguide (108) is designed in a disk shape and / or a cuboid shape and / or a cylindrical shape.

7. Optical light guide device (100) according to one of the preceding claims, wherein the light excitation element (117) comprises a third excitation element (132), wherein the third excitation element (132) can be excited by a third light (130) with a third wavelength (304) different from the first wavelength (300) and the second wavelength (302), or the third light (130) can be output through the third excitation element (132), wherein the waveguide (108) is configured to guide the third light (130), wherein the waveguide (108) comprises a third holographic element (126) for forming a third light path (128) for the third light (130) to or from the third excitation element (132), which is different from the first light path (112) and the second light path (120), and wherein the waveguide (108) has at least one (112), the second light path (120) and the third light path (128) section.

8. Optical light guiding device (100) according to claim 7, wherein the first holographic element (110) and / or the second holographic element (118) and / or the third holographic element (126) are arranged on a first slide (208).

9. Optical light guide device (100) according to claim 7 or 8, wherein the first holographic element (110) and / or the second holographic element (118) and / or the third holographic element (126) comprises a plurality of sub-elements (200, 202, 204).

10. Optical light guide device (100) according to one of the preceding claims, with a further waveguide (138) for guiding the first light (114) and the second light (122), wherein the further waveguide (138) provides a further first holographic element (136) in the first light path (112) for the first light (114) through the first excitation element (116) and a further second holographic element (142) in the second light path (120) for the second light (122) through the second excitation element (124), wherein the further waveguide (138) has at least one section (206) comprising the first light path (112) and the second light path (120), in particular wherein the light excitation element (117) is arranged between the waveguide (108) and the further waveguide (138).

11. Optical light guide device (100) according to one of the preceding claims, comprising a controllable light source (102) for outputting the first light (114) and / or the second light (122) into the waveguide (108) and / or into the light excitation element (117), in particular wherein the controllable light source (102) comprises a laser light source (104), in particular a laser diode.

12. Method (800) for operating an optical light guide device according to any one of claims 1 to 11, wherein the method (800) comprises the following step: - Incident (805) of first light into a first path of a waveguide to excite a first excitation element and / or incident (805) of second light into a second path of the waveguide to excite a second excitation element.

13. Control unit (900) configured to perform and / or control the step (805) of the method (800) according to claim 12 in a corresponding unit (905).

14. Computer program product with program code for carrying out the method (800) according to claim 12, when the computer program product is executed on a control unit (900) according to claim 13.

15. Machine-readable storage medium on which the computer program according to claim 14 is stored.

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