Functionalised waveguide

Abstract

The invention relates to a functionalised waveguide, wherein the waveguide (1) has a transparent main body (6) with a front side (7) and a rear side (8), wherein the main body (6) has a coupling-in region (4) and a coupling-out region (5) spaced apart therefrom in a first direction (5), wherein the coupling-in region (4) comprises a diffractive structure (12) which deflects at least a portion of the radiation (L1), which comes from an object (9) and strikes said structure, in such a manner that the deflected portion is propagated as coupled-in radiation in the main body (6) through reflections up to the coupling-out region (5) and strikes the coupling-out region (5), wherein on the front side (7) and / or rear side (8) an anti-reflection layer (13, 14) is formed which transmits interference radiation, which would strike the diffractive structure (12) only after a reflection on the front side (7) and / or rear side (8), to the front side (7) and / or rear side (8) and thus suppresses the reflection on the front side (7) and / or rear side (8).

Description

[0001] Functionalized waveguide

[0002] The present invention relates to a functionalized waveguide which can be used, for example, in a detector system or a display screen.

[0003] Transparent surfaces made of glass or plastic, such as windows or windshields in cars, have a transparent base body and are generally used only to protect people or objects from environmental influences such as wind, temperature, particles or radiation.

[0004] There is increasing interest in providing such a transparent base body that provides additional optical functionality.

[0005] It is therefore an object of the invention to provide a transparent base body with additional optical functionality.

[0006] The invention is defined in the independent claims. Advantageous embodiments are specified in the dependent claims.

[0007] In the functionalized waveguide according to the invention, an anti-reflection layer is formed on the front and / or back side, which suppresses reflection of the interfering radiation at the front and / or back side, in particular by transmitting the interfering radiation at the front and / or back side. As a result, unwanted ghost images (or double images) of the object or other unwanted effects of the interfering radiation can be prevented or at least significantly reduced by means of the functionalized waveguide. Preferably, 100% or at least 90% or more than 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% of the interfering radiation is transmitted at the front and / or back side, whereby the desired suppression of the reflection of the interfering radiation at the front and / or back side is achieved.

[0008] A (e.g., partially transparent) coupling region and a coupling-out region spaced therefrom in a first direction can be provided or formed in the transparent base body. The coupling-in region can have a diffractive structure with which the transparency of the coupling-in region is maintained under normal viewing conditions over a wide angular and wavelength range. Thus, only a portion of the radiation impinging on a front side of the transparent base body can be deflected by the transparent coupling-in region in such a way that the deflected portion propagates as coupled-in radiation in the base body by reflection to the coupling-out region and impinges on the coupling-out region.

[0009] The reflections can, in particular, be total internal reflections on the front and / or back of the transparent base body. However, it is also possible that reflective layers or coatings, or partially reflective layers or coatings, are provided for this purpose.

[0010] The front and back of the transparent base body can be designed as flat surfaces. For example, the transparent base body can be designed as a plane-parallel plate.

[0011] However, it is also possible that the front and / or the back are curved.

[0012] The transparent base body can be made of glass and / or plastic. It can be a single piece or have a multi-layer structure.

[0013] In particular, the transparent base body can be transparent to radiation or light in the visible wavelength range. Furthermore, it can be transparent to the near infrared and / or infrared range.

[0014] The output region of the transparent base body can deflect at least a portion of the coupled radiation impinging on it such that the deflected portion exits the base body. This preferably occurs via the front or back of the transparent base body.

[0015] The coupling-in region and the coupling-out region can be designed such that they do not perform any optical imaging function other than deflection. However, it is also possible for the coupling-in region and / or the coupling-out region to provide an optical imaging function in addition to deflection and thus perform optical imaging. For example, the optical imaging function can implement the function of a converging lens or diverging lens, a concave or convex mirror, whereby the curved surfaces (centered or decentered) can be spherically curved, aspherically curved, or freeform surfaces.

[0016] The diffractive structure of the coupling region can be realized as a buried diffractive structure, as a diffractive structure between two substrates or as a diffractive structure formed on the front or back side.

[0017] Furthermore, the coupling-out region can have a diffractive structure. The diffractive structure of the coupling-out region can be formed as a buried diffractive structure or as a diffractive structure on the front or back side.

[0018] A reflective or transmissive volume hologram can be provided as the diffractive structure of the input or output region. Furthermore, the diffractive structure of the input or output region can be a transmissive or reflective relief grating.

[0019] If the coupling region is designed as a (reflective or transmissive) relief grating, it is preferable not to form the anti-reflection layer directly on the relief grating. For example, the relief grating can be formed on the front side of the transparent base body and the anti-reflection layer on the back side of the transparent base body (or vice versa).

[0020] If the coupling region is designed as a (reflective or transmissive) volume hologram, the antireflection layer can be formed directly on the volume hologram. In particular, the volume hologram can be designed as a stack of several individual volume holograms, with each individual volume hologram being optimized for a predetermined wavelength. For example, three individual volume holograms can be optimized for wavelengths from the red, green, or blue wavelength ranges, respectively. When the volume hologram is designed as a stack of several individual volume holograms, the antireflection layer is preferably formed as the first or last layer of such a stack.

[0021] The anti-reflection layer can preferably be designed such that it is transmissive (preferably only) for the predetermined wavelengths for which the diffractive structure (e.g., the volume hologram) of the coupling region is designed. Thus, the anti-reflection layer can have a transmissivity tailored to the acceptance characteristic of the diffractive structure of the coupling region (or of the volume hologram(s). Acceptance characteristic is understood here in particular to mean that for a certain direction or angle of incidence, there are certain wavelength spectra that are diffracted by the diffractive structure. In other words, acceptance characteristic is understood here in particular to mean that the diffractive structure, depending on the angle of incidence, only diffracts certain wavelength spectra or only radiation with certain wavelengths.

[0022] Furthermore, it is possible that the anti-reflection layer is designed as a broadband anti-reflection layer which is (preferably only) transmissive in the entire predetermined angle of incidence range for all wavelengths used.

[0023] The anti-reflection layer can be formed as a single layer or as a multi-layer system (for example as a multi-layer system, as an interference layer system and / or as a moth-eye anti-reflection layer).

[0024] The anti-reflection layer can be designed for an angle of incidence range of, for example, 80°-100°.

[0025] The anti-reflection layer can, in particular, be designed such that it does not influence the radiation coupled into the base body by the diffractive structure of the input coupling region, preventing it from propagating to the output coupling region through reflections. It can also be said that the optical properties, dimensions, and / or positioning of the anti-reflection layer are selected such that the radiation coupled into the base body by the diffractive structure of the input coupling region can propagate to the output coupling region through reflections.

[0026] For example, the dimensions and / or positioning of the anti-reflection layer can be selected such that the coupled-in radiation does not hit the anti-reflection layer. This can be easily achieved, for example, in the case where the anti-reflection layer is formed on the back of the base body and the diffractive structure of the coupling region is formed on the front of the base body. Furthermore, this can be easily achieved, for example, in the case where the anti-reflection layer is formed on the front of the base body and the diffractive structure of the coupling region is formed on the back of the base body. In this case, it is advantageous, for example, if the dimension of the diffractive structure of the coupling region in the first direction is in the range of 5-15 mm or 5-10 mm.The dimension of the anti-reflection layer in the first direction may preferably be equal to or smaller than the dimension of the diffractive structure of the coupling region in the first direction.

[0027] Furthermore, it is advantageous if the dimensions of the diffractive structure of the coupling region in the first direction are selected such that the radiation coupled into the base body by the diffractive structure of the coupling region does not strike the diffractive structure of the coupling region again after an initial reflection in the base body. This can be achieved, for example, by a suitable selection of the dimensions of the diffractive structure of the coupling region in the first direction. Advantageous values ​​are, for example, in the range of 5-15 mm or 5-10 mm.

[0028] The diffractive structure of the coupling region can be designed such that only the radiation coming from the object, which strikes the diffractive structure at an angle from a predetermined angle of incidence range, is diffracted by the diffractive structure and thereby deflected, wherein the optical properties of the anti-reflection layer(s) are selected such that the anti-reflection layer(s) transmit(s) radiation which strikes the anti-reflection layer(s) at an angle which lies in the predetermined angle of incidence range.

[0029] One could also say that the predetermined angle of incidence range defines a field of view. The anti-reflection coating(s) is / are preferably designed to be transmissive for at least this field of view.

[0030] The predetermined angle of incidence range can be rotationally symmetric.

[0031] Alternatively, the predetermined angle of incidence range may not be rotationally symmetric. Thus, the predetermined angle of incidence range may be larger in a first plane (xz plane), which is spanned by a normal to the diffractive structure and a normal to both the first direction and the normal to the diffractive structure, than in a second plane (yz plane), which is spanned by the normal to the diffractive structure (12) and the first direction.

[0032] Preferably, the ratio is not greater than 2:1 or not greater than 3:2.

[0033] The predetermined angle of incidence range can, for example, be in the range from 40° to 120° and in particular be 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110° or 120°. In particular, the predetermined angle of incidence range can be symmetrical to the normal to the diffractive structure. Thus, the predetermined angle of incidence range can, for example, be any range from + / - 20° to + / - 60° and in particular be a range from -20° to 20°, -25° to 25°, -30° to 30°, -35° to 35°, -40° to 40°, -45° to 55°, -50° to 50°, -55° to 55° or from -60° to 60°.

[0034] The anti-reflection layer(s) can be implemented in a wide variety of variants. In the simplest form, the anti-reflection layer can be formed or consist of a single layer, e.g., of MgFz (for example, on spectacle lenses), and in more complex designs, it can consist of tens to hundreds of layers, e.g., as in high-performance anti-reflection coatings on optics in ultrashort-pulsed lasers. Example materials are TiO2 and SiO2. The anti-reflection layer can be planar and / or implemented on additionally structured surfaces. Examples of this include so-called moth-eye structures and / or pyramidal surfaces, such as those implemented on monocrystalline silicon solar cells. Typically, customized anti-reflection layers can be designed and optimized using software solutions familiar to those skilled in the art.

[0035] Preferably, the anti-reflection layer completely covers the diffractive structure of the coupling region. For this purpose, the anti-reflection layer can be the same size as the diffractive structure or larger (e.g., 5-10% larger).

[0036] The output coupling region may further comprise a mirror surface, a prism, and / or a reflective or transmissive Fresnel structure. These variants can be provided as an alternative to the diffractive structure or in addition to the diffractive structure of the output coupling region.

[0037] Furthermore, a detector system with a functionalized waveguide according to the invention (including all further developments) is provided. The detector system can have a detector onto which the portion of the radiation deflected by the output region impinges. The detector can be connected to the front or rear side of the base body. In particular, a direct connection can be provided.

[0038] The detector system can in particular be designed as a camera so that a recording (e.g. a single image, several images or a video) of the object can be carried out.

[0039] Furthermore, the detector system can be designed such that at least one optically imaging element is arranged in the area between the detector and the front or back side. It is also possible for the area between the detector and the front or back side to be free of imaging optical elements. In other words, the radiation coupled out by the coupling-out region thus strikes the detector without passing through further optically imaging elements. In this case, it is advantageous if the coupling-out region has an optically imaging property in addition to deflection.

[0040] The functionalized waveguide can be designed to perform an infinity-to-infinity mapping. However, it is also possible for it to perform a finite-to-infinite mapping, an infinite-to-finite mapping, or a finite-to-finite mapping.

[0041] The detector system can of course also be designed such that at least one optically imaging element is arranged between the detector and the front or rear side. Furthermore, a projection system or a screen with a functionalized waveguide according to the invention (including all further developments) is provided. In particular, the functionalized waveguide according to the invention can be arranged, for example, with the rear side of the transparent base body on a front side of a screen (e.g. connected to this), so that light to be emitted from the screen via its front side enters the base body via the rear side of the base body to display a predetermined image, travels to the front side of the base body and exits via the front side of the base body. The anti-reflection layer, for example,The part of the light from the screen that hits the anti-reflective layer is transmitted by it, which can prevent unwanted stray light.

[0042] The system formed in this way, consisting of waveguide and screen, can be designed, for example, as a stand-alone screen (e.g. a screen for a computer), as a laptop screen, as a mobile phone, as a tablet, etc.

[0043] The screen can be developed in such a way that the described detector system (in particular with the described camera functionality) is provided. This can be used to record the object (e.g. a person looking at the screen). This can be achieved, for example, by recording a person looking at the screen in such a way that, for example, during a video telephony (or video conference), they are looking into the eyes of the person shown on the screen with whom the video telephony is being conducted, so that a natural impression is created during the video telephony. It is essential for this that the recording direction of the camera is, for example, perpendicular to the front of the screen, which is possible with the screen according to the invention due to the functionalized waveguide.This is advantageous over conventional solutions where the camera is positioned at the edge of the screen or within the screen frame, resulting in a shot of a person looking at the screen from an angle, from above, below, or from the side. This creates the familiar effect of the person being photographed appearing to look past you.

[0044] In the area of ​​the decoupling area or section, the screen may, for example, not have any LCD elements (or other image-generating elements) or may be transparent, for example. In particular, the decoupling area or section may be located in an area in which no image information is generated by the screen. It is also possible for no part of the screen to be formed in the area of ​​the decoupling area or section.

[0045] This can ensure, for example, that the portion of the coupled-in radiation deflected by the output region hits the detector. It is understood that the features mentioned above and those to be explained below can be used not only in the specified combinations, but also in other combinations or on their own, without departing from the scope of the present invention.

[0046] The invention is explained in more detail below using exemplary embodiments with reference to the accompanying drawings, which also disclose features essential to the invention. These exemplary embodiments are for illustrative purposes only and are not to be interpreted as restrictive. For example, a description of an embodiment with a large number of elements or components should not be interpreted to mean that all of these elements or components are necessary for implementation. Rather, other embodiments may also contain alternative elements and components, fewer elements or components, or additional elements or components. Elements or components of different embodiments may be combined with one another unless otherwise stated. Modifications and variations described for one of the exemplary embodiments may also be applicable to other embodiments.To avoid repetition, identical or corresponding elements in different figures are designated by the same reference numerals and are not explained more than once. The figures show:

[0047] Fig. 1 is a side view of an embodiment of a detector system according to the invention;

[0048] Fig. 2 is a plan view of the waveguide 1 of Fig. 1;

[0049] Fig. 3 is a schematic representation of the spectrally resolved, angle-dependent deflection efficiency of the transmissive volume hologram of the coupling region 4;

[0050] Fig. 4 is a schematic representation of the deflection efficiency for three different angles of incidence as a function of the wavelength;

[0051] Fig. 5 is a side view of a detector system with a waveguide without an anti-reflection coating;

[0052] Fig. 6 is a schematically enlarged view of the coupling area of ​​the side view of Fig. 5;

[0053] Fig. 7 is a side view of another embodiment of the detector system according to the invention;

[0054] Fig. 8 is a side view of a detector system with a waveguide without an anti-reflection coating;

[0055] Fig. 9 is a side view of another embodiment of the detector system according to the invention, and Fig. 10 is a side view of another embodiment of the detector system according to the invention.

[0056] The views according to Fig. 1 and 2 show an embodiment of the waveguide 1 according to the invention together with a detector system 2 in order to realize a camera 3.

[0057] The waveguide 1 comprises an input coupling region 4 and an output coupling region 5 spaced therefrom in a first direction (here along the y-axis) and can be designed as a plane-parallel plate 6 with a flat front side 7 and a flat rear side 8. The plane-parallel plate 6, which can also be referred to as the base body 6, is made of a transparent material, such as glass or plastic.

[0058] The detector system 2 and the lower part of the plate 6 with the coupling-out region 5 can be arranged in a housing G, shown only schematically in Fig. 1, so that a user cannot immediately recognize that it is a camera 3. A control unit S can be provided in the housing, which can control the execution of a recording and has, for example, a processor P and a memory M.

[0059] With the camera 3, an object 9 can be imaged in such a way that light beams emanating from the object 9 (a light beam L1 is shown as a representative example) enter the plate 6 via the front side 7 and are deflected by the input region 4 such that they hit the back side 8 at an angle such that total internal reflection takes place. The light beams L1 are thus guided by total internal reflection at the front side 7 and back side 8 to the output region 5, which causes a deflection in the direction of the back side 8 so that the light beams L1 exit the plate 6 via the back side 8. Of course, it is also possible to coat the front and back sides 7, 8 with a reflective or partially reflective coating (not shown in Figs. 1 and 2), so that the light beams are guided in the plate 6 from the input to the output region 4, 5 by reflections at the reflective or partially reflective coating.

[0060] By means of an objective 10 of the detector system 2, the light beams L1 are then focused onto a detector 11 of the detector system 2, so that the desired image of the object 9 can be recorded by means of the detector 11. In Fig. 1, the representation regarding the imaging properties of the objective 10 is purely schematic. The detector system 2 can also be designed such that no objective 10 is required. For example, it is possible for the output coupling region 5 to provide a desired imaging function (in addition to beam deflection). The input coupling region 4 can, for example, have a transmissive volume hologram 12 which has an angle of incidence-dependent wavelength selectivity, so that it has a high degree of transparency over a large angular and wavelength range. This means that only a portion of the light emanating from the object 9 and incident on the input coupling region 4 (orThe light beam L1 impinging on the transmissive volume hologram 12 is deflected in the manner described. Other light beams from object 9 propagate through the coupling region 4 (or through the transmissive volume hologram 12) and exit the plate 6 via the rear side 8. Thus, the coupling region 4 can be described as partially transparent.

[0061] Fig. 3 schematically shows the spectrally resolved, angle-dependent deflection efficiency for the transmissive volume hologram 12 of the coupling region 4 as a function of the angle of incidence (in the yz plane) of the corresponding light beam, with the wavelength plotted in pm along the x-axis and the angle of incidence plotted in ° along the y-axis. Fig. 4 shows the deflection efficiency for the angles of incidence + 20°, 0°, and - 20°, with the wavelength in nm plotted along the x-axis and the efficiency along the y-axis.

[0062] From Figs. 3 and 4, it can be seen that the transmissive volume hologram 12 of the coupling region 4 deflects radiation from the spectral range from 392 nm to 398 nm (Azentrai = 395 nm ± 3 nm) with high efficiency for an angle of incidence of -20° and thus couples it into the plane-parallel plate 6. For an angle of incidence of 0°, the high efficiency is present for the spectral range from 528 nm to 536 nm (Azentrai = 532 nm ± 4 nm), and for an angle of incidence of +20°, a high coupling efficiency is present for the spectral range from 600 nm to 610 nm (Azentrai = 605 nm ± 5 nm).

[0063] The coupling region 4 additionally has an anti-reflection layer 13 (Figs. 1 and 2) which is designed in such a way that it transmits light beams (a light beam L2 is shown as a representative example) which originate, for example, from the object 9 and would lead to an undesired ghost image on the detector 11, so that they exit the plate 6 via the rear side 8 and therefore cannot hit the detector 11. Without the anti-reflection layer 13, a portion of the light beams L2 would be reflected back at the rear side 8 - air interface in the direction of the front side 7, as is shown schematically in Fig. 5. To simplify the illustration, the reflected portion of the light beams is shown offset in the y-direction in Fig. 5.

[0064] Of this reflected portion of the light beam L2, which strikes the volume hologram 12 during the formation of the waveguide in Fig. 5, a certain portion is reflected at the air-front surface 7 interface and deflected by the volume hologram 12, as schematically shown in Fig. 6. This deflected portion of the light beam L2 is then guided to the output section 5 and coupled out in the same way as the deflected portion of the light beam L1, so that an undesirable ghost image is generated.

[0065] Fig. 6 shows, in an enlarged schematic view for an object 9', how the undesired ghost image can arise. Light rays L2i and L2z pass through the volume hologram 12 (without being deflected), are reflected at the air-back interface 8 (a first virtual image 9h is generated by the reflection at the air-back interface 8), pass through the volume hologram 12 again, are reflected at the air-front interface 7 (a second virtual image 9'2 is generated by the reflection at the air-front interface 7), and are then deflected by the volume hologram 12 such that they are guided in the plate 6 to the output region 5. These light rays L2i and L2z thus generate a second virtual image 9'2, which appears as a ghost image offset from the object 9' by twice the distance d from the front 7 to the back 8.

[0066] By providing the anti-reflection layer 13 according to Figures 1 and 2, such an undesirable ghost image is greatly reduced, since the light rays L2, L2i and L22 are transmitted by means of the anti-reflection layer 13 (Fig. 1) and are therefore no longer reflected at the air-back surface 8 interface.

[0067] Fig. 7 shows a modification of the embodiment according to Figs. 1 and 2. In the embodiment of Fig. 7, an anti-reflection layer 14 is formed on the front side 7 in front of the volume hologram 12. This prevents unwanted ghost images that may originate from light beams (a light beam L3 is shown as a representative example) that enter the plate 6 via the back side 8 and pass through the volume hologram 12. A portion of these light beams would then be reflected at the front side 7-air interface (as shown schematically in Fig. 8) and in turn strike the volume hologram 12, which would redirect a portion of it in the manner shown in Fig. 8, whereby this light would be guided in the plate 6 to the output section 5 and coupled out by means of the output section 5, leading to the unwanted ghost image.However, due to the anti-reflection layer 14 on the front side 7, the light beams L3 are transmitted (Fig. 7), so that such ghost images can be prevented.

[0068] In the embodiment of the waveguide 2 according to the invention shown in Fig. 9, the waveguide is applied to a screen 20 which is seated in a housing 21 which also houses the detector system 2. The system formed in this way can be designed, for example, as a stand-alone screen (e.g. a screen for a computer), a laptop screen, a mobile phone, a tablet, etc. The illustration in Fig. 9 is purely schematic and in particular not to scale. The rear side 8 of the base body 6 is connected (e.g. glued) to a front side 22 of the screen 20, so that the light (L3, L4) emitted by the screen 20 via its front side 22 enters the transparent base body 6 through the rear side 8 to generate a predetermined image on the screen 20, travels therein to the front side 7 and exits via the front side 7, so that a viewer can perceive the image generated by the screen 20.This light L3, L4 emitted by the screen 20 could, for example, lead to unwanted stray light in the area of ​​the coupling region 4. However, since the anti-reflection coating 14 is provided, the light rays L3 that might lead to stray light are transmitted and thus exit the base body 6 via the front side 7. Thus, the light emitted by the screen 20 does not lead to any unwanted stray light, and there is no unwanted reduction in brightness in the image generated by the screen 20 in the area of ​​the coupling region 4.

[0069] In the area of ​​the output section 5, the screen 20 has no LCD elements, for example, or is transparent, so that the light beams L1 deflected by the output section 5 can be focused by the lens 10 onto the detector 11. Thus, the output section 5 can be located in an area in which no image information is generated by the screen 20 (it should be noted that the illustration in Fig. 9 is schematic and not to scale).

[0070] Fig. 10 shows a modification of the embodiment according to Figs. 1 and 2, in which an anti-reflection layer 14 according to Fig. 4 is provided in addition to the anti-reflection layer 13, so that suppression of unwanted ghost images due to light beams L2 and L3 can be prevented.

[0071] The light beams L2, L3 shown in Fig. 1, 2, 7, 9 and 10 each strike the front side 7 and back side 8 respectively at right angles. Of course, the anti-reflection layers 13, 14 can be designed for a predetermined angle of incidence of the light beams L2, L3. This predetermined angle of incidence range can be, for example, 80°-100°. The angle of incidence here is understood in particular to mean the angle of the light beam L2 to the normal to the front side (i.e. 0° in Fig. 1) or the angle of the light beam L3 to the normal to the back side (i.e. 0° in Fig. 7) in the respective yz-plane (hereinafter also referred to as the second plane). The angle of incidence range in the xz-plane (hereinafter also called the first plane) can be the same size (in which case there is a rotationally symmetric angle of incidence range) or larger than the angle of incidence range in the y-z-plane, whereby a ratio of no greater than 2:1 or 3:2 can exist.The predetermined angle of incidence range is preferably symmetrical to the respective normal, so that for a predetermined angle of incidence range of, for example, 80°, the range from -40° to 40° is covered. The waveguide 1 according to Figs. 1, 2, 7, 9 and 10 can be designed such that neither the coupling region 4 nor the coupling region 5 has an imaging function. In this case, an infinity-to-infinity configuration of the waveguide 1 exists. One can also say that the waveguide 1 performs infinity-to-infinity imaging. The detector 11 can be, for example, a CCD detector or a CMOS detector.

[0072] Since the coupling region 4 has the transmissive volume hologram 12, the coupling via the transmissive volume hologram 12 results in dispersion within the coupled spectral range for every angle. If the output coupling region 5 has a transmissive volume hologram designed in the same way as the coupling region 4, the dispersion caused by the coupling region 4 is compensated, and all spectral components are deflected back to the corresponding angle.

[0073] As an alternative to the described infinity-to-infinity configuration of the waveguide 1, the coupling region 4 and / or the output coupling region 5 can, for example, have an imaging function in the form of a lens function or concave mirror function. This allows finite-to-infinity, infinity-to-finite, or finite-to-finite imaging configurations to be realized using the waveguide 1. In the coupling region 4, this can be used, for example, to record an object 9 that is positioned so close to the waveguide 1 that it can no longer be optically assumed to be an infinitely distant object. In the output coupling region 5, implementing such a lens or concave mirror function makes it possible to immediately convert the output angular spectrum into a spatial distribution in the focal plane of this implemented lens or mirror function. In this case, the objective lens 10 can, for example, be omitted.In this case, one can say that the detector system 2 comprises the detector 11 as well as the lens and / or concave mirror function of the output coupling region 5. Since the lens 10 can be omitted, the detector 11 can be positioned and / or attached, for example, directly on the back side 8 of the waveguide 1, thereby achieving a very high degree of integration, minimal volume, and high robustness.

[0074] The described reflective volume holograms for the input coupling region 4 and the output coupling region 5 can be produced, for example, by illuminating a photosensitive volume holographic material 12, which is integrated into the waveguide 1, with a reference wave having a wavelength of 532 nm, which is incident on the front side 7 at an angle of incidence of 0°, and a signal wave having the same wavelength, which is incident on the rear side 8 at an angle of incidence of 60°. The reference wave and the signal wave originate from the same laser, so that an interference field or interference volume is created across the photosensitive volume holographic material, where corresponding refractive index modifications can develop. Photosensitive glasses, dichromate gelatins, or photopolymers can be used as photosensitive volume holographic materials.These can, for example, be applied to a PC film (polycarbonate film) and exposed there accordingly. The film can then be laminated to a substrate for the waveguide 1 to produce the waveguide 1. The film can, for example, be laminated only in the area of ​​the input coupling region 4 and the output coupling region 5. Alternatively, full-surface lamination over the entire waveguide surface is possible, whereby only the corresponding input and output coupling functions are exposed in the input and output coupling regions. To protect the volume holograms, it is advisable to apply another substrate to the laminated volume hologram. This creates a layer stack with the following basic structure: transparent substrate, cement or adhesive layer, volume hologram, cement or adhesive layer, transparent substrate.

Claims

Patent claims Functionalized waveguide, wherein the waveguide (1) has a transparent base body (6) with a front side (7) and a back side (8), wherein the base body (6) has a coupling-in region (4) and a coupling-out region (5) spaced therefrom in a first direction, wherein the coupling-in region (4) comprises a diffractive structure (12) which deflects at least a portion of radiation (L1) coming from an object (9) and impinging on it in such a way that the deflected portion propagates as coupled-in radiation in the base body (6) by reflections to the coupling-out region (5) and impinges on the coupling-out region (5), which deflects at least a portion of the coupled-in radiation impinging on it in such a way that the deflected portion exits the base body (6), wherein an anti-reflection layer (13, 14) is formed on the front side (7) and / or back side (8), which anti-reflection layer,which would only strike the diffractive structure (12) after a reflection at the front side (7) and / or back side (8), is transmitted at the front side (7) and / or back side (8) and thus suppresses the reflection at the front side (7) and / or back side (8). Waveguide according to claim 1, wherein a first anti-reflection layer (13, 14) is formed on the front side (7). Waveguide according to claim 1 or 2, wherein a second anti-reflection layer (13, 14) is formed on the back side (8). Waveguide according to one of the above claims, wherein the anti-reflection layer(s) (13, 14) completely covers / cover the diffractive structure (12). Waveguide according to one of the above claims, wherein the first anti-reflection layer (13, 14) and / or the second anti-reflection layer (13, 14) are / is designed to transmit the radiation (L1) coming from the object (9) to be detected.

6. Waveguide according to one of the above claims, wherein the diffractive structure (12) is designed as a transmissive or reflective volume hologram.

7. Waveguide according to one of the above claims, wherein the optical properties, the dimensions and / or positioning of the anti-reflection layer(s) (13, 14) are / is selected such that the radiation coupled into the base body (6) by the diffractive structure (12) of the coupling-in region (4) can propagate by reflections to the coupling-out region (5).

8. Waveguide according to one of the above claims, wherein the dimension of the diffractive structure of the coupling region in the first direction is selected such that the radiation coupled into the base body (6) by the diffractive structure (12) of the coupling region (4) does not strike the diffractive structure (12) of the coupling region (4) again after a first reflection in the base body (6).

9. Waveguide according to one of the above claims, wherein the diffractive structure (12) of the coupling region (4) is designed such that only the radiation coming from the object (9) which strikes the diffractive structure (12) at an angle from a predetermined angle of incidence range is deflected by the diffractive structure (12), wherein the optical properties of the anti-reflection layer(s) (13, 14) are selected such that the anti-reflection layer(s) (13, 14) transmit(s) radiation which strikes the anti-reflection layer(s) (13, 14) at an angle which lies in the predetermined angle of incidence range.

10. Waveguide according to claim 9, wherein the predetermined angle of incidence range is rotationally symmetric.

11. Waveguide according to claim 9, wherein the predetermined angle of incidence range in a first plane (xz-plane) spanned by a normal to the diffractive structure (12) and a normal to both the first direction and the normal to the diffractive structure is greater than in a second plane (yz-plane) spanned by the normal to the diffractive structure (12) and the first direction, preferably a ratio of not greater than 2:1 or 3:

2. Waveguide according to one of the above claims, wherein the anti-reflection layer(s) is / are designed such that it is / are transmissive for the predetermined wavelengths for the diffractive structure (12) of the coupling region (4). Waveguide according to one of the above claims, wherein the anti-reflection layer(s) is / are designed such that it has / have a transmissivity designed for the acceptance characteristic of the diffractive structure (12) of the coupling region (4). Waveguide according to one of claims 1 to 11, wherein the anti-reflection layer(s) is / are designed such that it is / are transmissive for all wavelengths used in the entire predetermined angle of incidence range of the diffractive structure (12) of the coupling region (4). Detector system with a functionalized waveguide (1) according to one of the above claims.Detector system according to claim 15, wherein the detector system comprises a detector (2) onto which the portion of the radiation deflected by the coupling-out region (5) impinges. Detector system according to claim 15 or 16, wherein the detector system comprises a screen (20) with a front side (22) which can emit light (L3, L4) via the front side (22) to display an image, wherein the base body (6) is attached with its rear side (8) to the front side (22) of the screen, such that the light (L3, L4) coming from the screen (20) passes through the base body (6) and exits via the front side (7) of the base body (6), wherein the portion (L3) of the light (L3, L4) coming from the screen (20) which impinges on the anti-reflection layer (13, 14) is transmitted by the latter.

Images