DETECTOR SYSTEM

Description

[0001] The present invention relates to a detector system for a display device, wherein the detector system provides a non-contact input interface.

[0002] Display devices are now frequently designed with a user-friendly interface. This functionality is commonly known as a "touchscreen" and improves the usability of the display device. Furthermore, it eliminates the need for additional human-machine interfaces (HMIs), such as a mouse or keyboard. Touchscreen technology is now widespread and is used, for example, in laptops, point-of-sale systems, smartphones, and multifunction displays in vehicles.

[0003] There are currently three common solutions for touchscreens. One type is resistive touchscreens, where the display reacts to pressure or resistance. The pressure point is detected by a resistance matrix, processed in the controller, and interpreted as input by the operating system.

[0004] Inductive touchscreens are typically operated with a stylus that has a coil integrated into its tip. A network of conductive traces on the display induces current in the stylus's coil. The stylus then sends a signal that detects its precise position. The stylus itself does not need to touch the touchscreen surface.

[0005] Capacitive touchscreens can be operated with any conductive object. These types of touchscreens are currently used in almost all new smartphones. In these touchscreens, a grid of conductive traces is integrated into the glass layers. When the display surface is touched, the electric field changes. Changes in capacitance within the grid allow the point of contact to be determined. Capacitive touchscreens are multitouch-capable, meaning that more than one touch point can be recognized and processed simultaneously.

[0006] In graphic applications, a trend towards augmented reality (AR) continues to be evident. This refers specifically to the computer-aided enhancement of reality perception. Information (e.g., image content, virtual objects) is visually represented by being superimposed and / or overlaid onto the real image. Efforts are currently underway to develop user interface concepts for augmented reality solutions. Control and input are currently based on three main approaches.

[0007] Gesture recognition can be performed in this way. Systems with external sensors are used to recognize human gestures and interpret them using a computer. The most commonly used methods are camera-based gesture recognition, ultrasound-based gesture recognition, LIDAR (Light Detection and Ranging), and RADAR (Radio Detection and Ranging).

[0008] Camera-based gesture recognition uses one or more cameras to capture images of gestures. These images are then compared and interpreted using software (descriptors) against a database. These cameras can utilize various technologies, such as time-of-flight, structured light, or stereoscopy.

[0009] In ultrasound-based gesture recognition, a microchip generates high-frequency sound waves that are reflected by an object. The reflected waves can then be recaptured by the chip. The position and direction of movement can be determined by analyzing the time of flight, phase, and / or frequency shift.

[0010] LiDAR measures distances by measuring the travel time of emitted light signals. Radar measures distance and direction based on the travel time of emitted electromagnetic waves and their reflection from the object.

[0011] Furthermore, a widely used method for controlling graphical augmented reality solutions is the use of an HMI (Human-Machine Interface). The "Loop" joystick ring of the "Focals" smart glasses serves as an example. The interface forwards the commands entered by the user to the operating system for processing.

[0012] Furthermore, voice control is possible. Here, commands are transmitted via voice to a module that can record and interpret the spoken input.

[0013] However, the aforementioned current operating concepts have some disadvantages.

[0014] With touchscreen technology solutions, the display becomes dirty from touching the surface, which can impair functionality. This also presents hygiene concerns, especially in public spaces (e.g., restaurants) or medical facilities. Furthermore, scratches on the display surface can cause usability issues. Capacitive solutions require input via a conductive object. This is cumbersome or impossible when wearing gloves, for example. Liquids on the surface can also interfere with operation. Resistive solutions require the surface to be made of an elastic material (e.g., plastic), making the display prone to scratches. Inductive solutions require a separate HMI device (e.g., a stylus).

[0015] Augmented reality control has the problem that voice controls only work for the stored languages ​​and are susceptible to interference from background noise. Input via a human-machine interface (HMI) necessarily requires an additional device, the HMI itself. Gesture recognition is only effective under certain lighting conditions and depends on the camera resolution and the processing power of the computer system.

[0016] Furthermore, WO 2014 / 137754 A2 is known, which describes a method for detecting a non-contact input above a surface, in which holographic elements are used to couple light into an optical waveguide.

[0017] Based on this, the object of the invention is therefore to provide a detector system with an improved input interface. The invention is defined by the detector system according to claim 1. Advantageous embodiments are specified in the dependent claims.

[0018] The detector system according to the invention can comprise a waveguide having a transparent base body with a front and a back side, a display device that presents several selection areas such that they are perceptible in a display area of ​​the base body when viewing the front side, a sensor device having an associated sensor section for each selection area, and a control device. The base body can include a diffractive element in the display area and an output coupling area spaced apart from the display area, which has an associated output coupling section for each selection area.Of the radiation striking the diffractive element in the display area via the front, at least a part can be deflected by the diffractive element depending on the selection area such that the deflected part is propagated as coupled radiation in the base body by reflection (or reflections) to the output coupling area and strikes the associated output coupling section, wherein the output coupling area couples at least a part of the coupled radiation striking it out of the base body in such a way that the part coupled out by an output coupling section strikes the associated sensor section of the sensor device, which continuously measures the intensity of the incident radiation and supplies it to the control device.Depending on a change in intensity caused by positioning an object in front of the front of the base body and in front of a selection area of ​​the display area, the control unit can determine whether a selection area has been selected.

[0019] Thus, the measured change in intensity can be used to determine whether, and if so, which of the selection areas of the display range has been selected.

[0020] In the solution according to the invention, the approach of an object (for example, a finger or a hand) to the selection area can cause a change in the light intensity in this area. This, in turn, causes a change in the light intensity on the associated sensor section. The precise location of the input on the display device and / or the distance of the object from the front of the base body can then be interpreted, for example, via the voltage change on the sensor. It is advantageous if both the diffractive element in the display area and the output coupling section are designed as volume holograms embedded in the base body, acting as input and output coupling grids. Together with the base body, the holograms form a holographic waveguide. Within this waveguide, light of a specific wavelength or spectral bandwidth, or light of a specific angle or angular range, can be guided from the input coupling grid to the output coupling grid.The guidance within the base body is preferably achieved by internal total reflection at the front and back at a deflection angle determined by the volume hologram.

[0021] The detector system according to the invention provides a non-contact area sensor and enables, for example, the following new applications or improvements. For instance, it allows for the integration of a visualization behind a pane of glass (e.g., a shop window), enabling interaction even from a short distance. A transparent, semi-transparent, or opaque display can be created and operated, where the content (selection area) is shown in front of, within, or behind the display plane. This results in improved input recognition and ergonomics compared to other gesture-recognizing camera solutions.

[0022] Furthermore, operation using objects of all kinds (conductive or non-conductive) is possible. It exhibits low susceptibility to interference under varying lighting conditions and requires no database, unlike voice input systems. There is also a wide selection of materials available for the transparent base body. It is a purely optical system, eliminating the need for various functional layers (e.g., with laser engravings, wires, etc.). Moreover, the front of the base body remains uncontaminated by touchless operation.

[0023] The display unit can be spaced apart from the transparent base body or connected to it. Furthermore, the base body can be integrated into the display unit itself. The display unit can be designed as an active display unit or as a passive display unit.

[0024] The diffractive element in the display area can be embedded within the transparent base body. Preferably, the diffractive element is designed as a volume hologram. Of course, the diffractive element can also be designed as a two-dimensional grid. In this case, it can be embedded within the base body or positioned on the front or back. The diffractive element can also be a relief grid.

[0025] The same applies to the output area. The output area can have a diffractive element. The diffractive element of the output area can be further developed in the same way as the diffractive element of the display area. It is particularly preferred if a volume hologram is formed in both the display area and the output area.

[0026] The transparent base body is preferably designed as a plane-parallel plate and can be made of plastic or glass. However, it is also possible for the front and / or back of the transparent base body to be curved. Furthermore, it is possible for the front and back to be planar but not parallel to each other, so that the transparent base body has a wedge shape.

[0027] The output coupling area can be designed to couple the radiation out via the front, back, or end face of the transparent base body.

[0028] The selection areas can be arranged side-by-side (with a gap or directly adjacent) in a first direction. Furthermore, the selection areas can be arranged side-by-side, directly adjacent, or spaced apart in a second direction that differs from the first.

[0029] The same applies to the decoupling sections of the decoupling area.

[0030] The lens function of the diffractive element can be configured such that a separate lens function is provided for each selection area. The focal points of these lens functions preferably lie in a focal plane, which is located, in particular, in front of the front surface.

[0031] Furthermore, the lens function of the output coupling area can be designed such that each output coupling section has a lens function. The focal points of these provided lens functions preferably lie in the plane of the sensor device.

[0032] The lighting device can be designed in particular such that a diffractive element is provided for coupling out lighting radiation in the area of ​​the selection zones.

[0033] The diffractive element in at least one selection area and / or at least one output coupling section (preferably the associated output coupling section) can exhibit a wavelength-dependent imaging characteristic with longitudinal chromatic aberration. This means that the position of the focal points along the optical axis of the imaging characteristic differs for different wavelengths. The sensor device can measure the wavelength-dependent intensity of the incident rays and transmit this information to the control device, which then determines the distance of the object from the front of the base body based on the measured wavelength-dependent intensity.

[0034] The detector system is specifically designed to measure or detect only distances greater than zero, in order to enable non-contact distance detection.

[0035] Depending on a specific distance, the control unit can change the value of a measurement and / or output parameter, or any other parameter. This could be, for example, the volume of an audio output, the brightness of a display, the sensitivity of a measured quantity, or something similar. By measuring the distance, the value can advantageously be adjusted or set continuously in a simple manner.

[0036] Such an adjustment (preferably continuous adjustment) of a parameter can also be achieved by designing the multiple selection areas as different sizes of the parameter, so that the size adjustment is carried out by moving the object over the selection areas in the manner of a slider.

[0037] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations given, but also in other combinations or on their own, without leaving the scope of the present invention.

[0038] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings, which also disclose essential features of the invention. These exemplary embodiments serve only for illustration and are not to be interpreted as limiting. For example, a description of an exemplary embodiment with a plurality of elements or components is not to be interpreted as meaning that all of these elements or components are necessary for implementation. Rather, other exemplary embodiments may also contain alternative elements and components, fewer elements or components, or additional elements or components. Elements or components of different exemplary embodiments may be combined with one another unless otherwise specified. Modifications and variations described for one of the exemplary embodiments may also be applicable to other exemplary embodiments.To avoid repetition, identical or corresponding elements in different figures are designated with the same reference symbols and are not explained multiple times. The figures show: . Fig. 1 a schematic representation of an embodiment of the detector system according to the invention; Fig. 2 a view of the front side 7 of the base body 6 of the detector system 1 in Fig. 1 Fig. 3 shows a view of the sensor device 4 of the detector system of Fig. 1 Fig. 4 a view of the front of a further base body 6 according to a further embodiment of the detector system 1 according to the invention; Fig. 5 a view of the front 7 of a further embodiment of the base body 6 of a further detector system 1 according to the invention; Fig. 6 a side view of the detector system 1 of Fig. 5 Fig. 7 a schematic representation to illustrate a further embodiment of the detector system 1 according to the invention; Fig. 8 a schematic representation to illustrate a further embodiment of the detector system 1 according to the invention; Fig. 9 a view of the front side 7 of a transparent base body 6 of a further embodiment of the detector system 1 according to the invention; Fig. 10 a side view of the detector system 1 of Fig. 9 Fig. 11 a view of the front side 7 of the base body 6 of a further embodiment of the detector system 1 according to the invention; Fig. 12 a view of the front side 7 of the base body 6 of a further embodiment of the detector system 1 according to the invention; Fig. 13 a view of the front side 7 of the base body 6 of a further embodiment of the detector system 1 according to the invention; Fig. 14 a view of the front side 7 of the base body 6 of a further embodiment of the detector system 1 according to the invention; Fig. 15 a side view of the detector system 1 of Fig. 14 ; Fig. 16 a schematic representation of a further embodiment of the detector system according to the invention, and Fig. 17 a schematic representation of a further embodiment of the detector system according to the invention.

[0039] At the in Fig. 1 In the embodiment shown, the detector system 1 according to the invention comprises a waveguide 2, a display device 3, a sensor device 4 and a control device 5.

[0040] The waveguide has a transparent base body 6 with a front surface 7 and a back surface 8. In the embodiment described here, the base body 6 is designed as a plane-parallel plate, so that both the front surface 7 and the back surface 8 are planar. The base body 6 can be made of, for example, glass or plastic.

[0041] The basic body 6 comprises a coupling area 9 and a coupling area 10 spaced apart from it, wherein a volume hologram 11, 12 is formed both in the coupling area 9 and in the coupling area 10.

[0042] As schematically in Fig. 1 As depicted, at least a portion of a radiation 13 entering the transparent base body 6 via the front surface 7 and striking the volume hologram 11 of the coupling area 9 is deflected by the volume hologram 11 such that the deflected portion is guided as coupled radiation by reflections at the back surface 8 and front surface 7 to the volume hologram 12 of the output coupling area 11. The reflections at the back surface 8 and the front surface 7 can be total internal reflections. However, it is also possible that the front surface 7 and the back surface 8 are partially reflective or reflectively coated, at least in the area responsible for guiding the coupled radiation.

[0043] At least a part of the coupled radiation striking the volume hologram 12 of the output coupling area 10 is deflected by means of the volume hologram 12 in such a way that it exits the transparent base body 6 via the back side 8 and strikes the sensor device 4 positioned behind the back side 8.

[0044] Behind the rear side 8 of the transparent base body 6, the display device 3 is arranged, which can be, for example, an LCD display. The display device is designed and / or controlled by the control device 5 such that it displays several selection areas A1, A2, A3, A4, A5, A6 in the coupling area 9. This is shown in the view of the front of the transparent base body in Fig. 2 The letters A, B, C, D, E, and F are used as examples. Each letter represents a single selection area. The rectangular frame around each letter can be displayed or omitted. Of course, the display is not limited to the letters shown. For example, any image, symbol, number, multiple letters, or text can be displayed.

[0045] The coupling area 9 can therefore also be referred to as the display area 9 of the base body 6, in which selectable selection areas are displayed in such a way that they are perceptible when viewing the front side 7.

[0046] The volume hologram 11 of the coupling region 9 is configured such that each selection region A1–A6 is assigned a coupling section 91, 92, 93, 94, 95, and 96. Each of these coupling sections 91–96 is assigned an outcoupling section 101, 102, 103, 104, 105, and 106, on which the portion of the coupled radiation deflected by the corresponding coupling section 91–96 strikes, as indicated by the dashed lines 131, 132, 133, 134, 135, and 136.

[0047] As in Fig. 3 As shown schematically, the sensor device 4 is designed as a line sensor with six sensor sections 41, 42, 43, 44, 45 and 46, wherein each sensor section 41-46 is assigned to one of the output sections 101-106. Thus, the radiation coupled out by output section 101 strikes sensor section 41.

[0048] The sensor device 4 continuously measures the intensity of the sensor sections 4 1 -4 6 and transmits these measurement results to the control device 5, which has a processor for performing the corresponding calculation and control.

[0049] If a user wants to select the selection area with the letter A, for example, they can position their finger 14 in front of the front surface 7 of the base body 6 and in front of the selection area with the letter A (without touching the front surface 7). This causes a change in the light intensity in front of the coupling section 9 1 (less light is coupled in via the coupling section 9 1 because the finger 14 causes some shading). Through the coupling of light via the corresponding coupling section 9 1 and the guiding of the coupled light 13 1 to the output coupling section 10 1, which directs the light onto the sensor section 4 1, the sensor section 4 1 will measure a lower light intensity and transmit this measurement to the control unit 5. Based on the reduced intensity, the control unit 5 can determine that the selection area with the letter A has been selected.

[0050] This provides a non-contact surface sensor that is universally applicable and exhibits low susceptibility to interference even under different lighting conditions.

[0051] The transparent base body 6 can be spaced apart from the display device 3 (hereinafter also referred to as display assembly 3), as shown schematically in Fig. 1 as shown. However, it is also possible that the base body 6 is connected to the display device 3. In particular, the display device 3 itself can be used as a transparent base body 6. In this case, only the volume holograms 11 and 12 need to be formed in the display device 3, so that the transparent base body 6 is then realized by the display device 3. In particular, the display device 3 can contain an optoelectronic element (for example, an LCD element or an OLED element) that is embedded in the base body 6, as schematically shown in Figur 16 The display devices 3 described so far can therefore also be referred to as active display devices 3.

[0052] Furthermore, it is possible to use a holographic element 23 (e.g., a holographic diffuser) for the display devices 3, which can also be embedded in the base body 6, as in Figur 17 The holographic element is shown schematically. Dynamic or static content can be displayed using the holographic element. The illumination (or reconstruction of the hologram as part of the display device 3) can be implemented in various ways. For example, active illumination L1-L3 can be provided, with illumination L1 located at the rear 8, illumination L2 at the front, and illumination L3 at the front 7. Of course, preferably only one of the three illuminations L1-L3 is provided. Alternatively, the hologram can also be designed so that illumination is achieved with sunlight (indicated by arrow L4). The illumination L1-L3 can be referred to as active illumination, and the illumination with sunlight can be referred to as passive illumination.

[0053] In Fig. 4 An embodiment is described in which two sets of six coupling sections 91-96 and 97, 98, 99, 910, 911, and 912 are provided. These two sets of six coupling sections 91-96 and 97-912 are arranged vertically one above the other (one above the other in the propagation direction). The associated twelve decoupling sections 101-106 and 107, 108, 109, 1010, 1011, and 1012, on the other hand, are spaced apart from each other in the horizontal direction, as shown in Fig. 4 As shown. Behind these two areas of output sections 101-106 and 107-1012, two areas with six sensor sections each are arranged, so that each input section 91-912 is assigned a sensor section via the output sections 101-1012. The output sections 101-106 and 107-1012 are spaced apart horizontally to achieve resolution in the vertical direction (propagation direction) and to avoid, as far as possible, interference with the sections of the volume hologram 11 of the input area 9. Therefore, the propagation angles to the output sections 101-1012, and thus to the sensor sections of the sensor device 4, are as different as possible from those to the input sections 91-96 and 97-912.

[0054] At the in Fig. 4 In the solution shown, the output sections 101–1012, and thus the sensor sections of the sensor device 4, are formed at different locations on the transparent base body 6. Alternatively, it is possible to select the largest possible distances within the output sections 101–1012 for the different vertical input options (input sections 91–96 on the one hand and input sections 97–912 on the other). This naturally also applies to the sensor sections of the sensor device 4. By comparing the voltage differences on the individual sensor sections, the correct input value can then be reliably detected.

[0055] In Fig. 5 An embodiment is shown in which the sensor device 4 has a 2D RGB sensor which is positioned behind the rear side 8, as in Fig. 6 is shown. In this embodiment, the different selection areas are arranged in the horizontal direction (double arrow 15) as in the version in conjunction with Fig. 4 In the described embodiment, the propagation angle is used to resolve the different selection areas in the vertical direction (double arrow 16). To achieve this, the volume hologram 11 of the coupling area 9 is designed to diffract the incident light according to its position in the horizontal and vertical directions. This diffraction ensures that for each selection area (and thus for each coupling section 91-915), a correspondingly different combination of propagation angle and wavelength arrives at the coupling area 10 or coupling sections 101-1015, and thus at the sensor sections of the sensor device 4. The control device 5 can then interpret the corresponding values ​​from the sensor device 4.

[0056] At the in Fig. 7 In the illustrated embodiment, an embedded lens function is used for input recognition, preferably integrated into the volume hologram 12 of the output coupling area 10. The selectivity of the object point can be adjusted by imprinting a strong angular dependency into the volume hologram 12 of the output coupling area 10. For this purpose, a holographically embedded lens is integrated into each output coupling section 101-1012, the effect of which is shown schematically in the diagram. Fig. 7 The focal length of this exposed lens lies in a focal plane 17 in front of the front surface 7 of the transparent base body 6 and defines the distance of the object 14 to be detected from the front surface 7 at which the object 14 is ideally imaged onto the sensor device 4. Fig. 7 Furthermore, the intensity distribution 18 is schematically shown for each coupling section 101–104 for the object 14 when positioned within the focal plane 17 (solid line) and when positioned in front of the focal plane 17 (dashed line). Different contrast areas (spots) are thus created on the sensor device 4, which are assigned to the individual selection areas (coupling sections 91–94). When an object 14 comes close to the focal plane 17, changes in intensity are registered at the sensor device 4. Thus, a spatial resolution of the input can be determined. By setting a threshold value for the intensity at the focal point, the input can be processed for an application. As in Fig. 7 As shown schematically, the light intensity or contrast on the sensor device 4 is greater the closer the object 14 is to the focal plane 17. The aberrations increase with increasing distance of the object 14 from the respective optical axis OA 1, OA 2, OA 3 and OA 4. Furthermore, in Fig. 7 The sensitive angle range 19 of the coupling section 9 1 is also shown.

[0057] This described change in contrast with distance to the focal plane 17 can also be evaluated in such a way that the distance of the object 14 to the focal plane 17 (and thus also to the front surface 7) is detected. This change in distance to the focal plane 17 (or to the front surface 7) can be used as input for setting a parameter, such as controlling the volume of an audio output. For example, the volume can be increased when the object 14 is moved towards the focal plane 17, thereby decreasing the distance to the focal plane 17. Other parameters can also be controlled in this way, such as the brightness of the display area or other display parameters.

[0058] The distance of object 14 to the front face 7 can also be determined by spectral resolution.

[0059] This is shown schematically in Fig. 8 As shown, both the volume hologram 11 of the coupling section 9 1 and the volume hologram 12 of the output coupling section 10 1 are each designed with a lens function. Depending on the spectral value or wavelength, the focal plane of the volume hologram 11 for the coupling section 9 1 is located at a different distance from the front face 7 of the transparent base body 6. The distance decreases from blue to green to red and infrared (especially NIR). If the coupling area 9 is actively illuminated and the wavelength of the illumination is known, the focal plane and thus the distance to the front face 7 of the transparent base body 6 are also known.

[0060] The lens function in the volume hologram 12 of the output coupling section 10 1 has the same spectral characteristic, so that the distance to the back side 8 decreases from blue to green to red and infrared.

[0061] The sensor device 4 is designed as a spectrally selective sensor device 4 and can, for example, include an RGB sensor. The control device 5 can then use the intensity values ​​as a function of the corresponding wavelengths to detect the selection of the appropriate coupling section 9 1. Additionally or alternatively, the distance of the object 14 to the front surface 7 can be detected, which in turn allows a parameter (such as the volume) to be controlled.

[0062] Up to this point, holograms 11 and 12 have always been described as volume holograms. Of course, different hologram types can be used. In particular, diffractive elements and especially relief gratings can be employed. However, the advantage of using volume gratings and volume holograms lies in their selectivity at angle and wavelength. Due to the filter function, stray light (radiation irrelevant to the solution's function) cannot be coupled in and / or passed on to the sensor device 4. This can contribute to higher precision and robustness.

[0063] In the embodiments described so far, the selection areas AF are located next to each other. Interference (e.g., from stray light) can be reduced if each selection area has a different coupling grating and the propagation angles of adjacent selection areas are chosen to be as different as possible, as shown schematically below for selection areas A, B, and C. Fig. 9 und 10 is shown.

[0064] Another way to reduce interference is related to Fig. 11 As described, the object 14 used for input is actively illuminated from the display plane. The reflected light can be captured and used to select the input. This reduces interference caused by potentially unwanted shadowing. Furthermore, this enables use in darkness.

[0065] The active lighting can be implemented, for example, by an LED frame 20 around the coupling area 9 ( Fig. 11 However, a second hologram 21 can also be projected around the coupling area 9 ( Fig. 12 ) or under the volume hologram 11 of the coupling area 9 ( Fig. 13 ) can be used for this purpose, whereby the second hologram 21 can, for example, couple out white light which is coupled in from a defined point 22 of the transparent base body 6. It is only necessary to ensure that the propagating waves of the second hologram 21 and the volume hologram 11 of the coupling area 9 do not interfere with each other. Due to the illumination function from a micro-optical structure in the transparent base body 6, the transparent base body 6 itself can remain transparent.

[0066] Active lighting can also be achieved by illuminating the selection areas on the front 7 from within the base body 6. The source of the coupled light can be selected differently in each location, as shown schematically in Fig. 13 is shown.

[0067] To optimize the beam guidance and arrangement of the propagation angles, the volume hologram 11 for the coupling area 9 does not need to cover the entire area of ​​the selection areas, but can also be very narrow, as in Fig. 14 As indicated, an input grid 11 exposed by a plane wave can be divided into several strips 111, 112, which can then be used to couple the respective selection areas in the vertical direction. This ensures that the beams, after coupling, do not encounter another input grid 11 on their way to the output coupling area 10, as they would otherwise interfere and thus could not be resolved at the sensor device 4. By dividing the input grid 11 into input strips 111, 112, larger areas in the transparent base region 6 can be functionalized and inputs can be reliably read out. Furthermore, it becomes easier to find suitable propagation angles for transporting the radiation to the output coupling area 10, and for detection, several lines in the input coupling area 9 can use only one output grid with a photosensitive chip (sensor device 4).

[0068] In order for a complete image to result at the sensor device 4 of the output coupling grid 12 in the described embodiment, the vertical height of the input coupling grid 11 must be equal to that of the sensor device 4. To achieve optimal resolution despite differing heights, a lens function can be incorporated into the output coupling grid 12. This lens function ensures that the radiation from the individual input coupling strips 111, 112 of the input coupling grid 11 is projected back onto the sensor device 4 via the output coupling grid as a complete image with correct scaling (as schematically shown in [reference]). Fig. 16 (as shown).

[0069] In the case of ambient light, the detector system 1 described here may misinterpret the light intensity changes on the sensor device 4. To reduce this, the control unit 5 can compare light values ​​from all selection ranges and define values ​​that do not change over time as static values. These values ​​can be disregarded when evaluating the intensity changes. Thus, light values ​​that are not relevant to the application can be filtered out as background noise, and the actual calculation of the intensity change for identifying an input becomes more reliable.

[0070] Another way to improve the robustness of detector system 1 is to expose a lens function on the input and output coupling grids. This allows intensity differences to be registered much better and reduces misinterpretations in the input.

[0071] Furthermore, with an integrated lens function at the coupling grating, the light from the coupling grating to the output grating can be guided parallel or as a parallel beam. This reduces light loss on the way to the sensor device 4 and minimizes stray light.

[0072] When an object 14 approaches a selection area, a specific change in light intensity arrives at the output coupling grid within a certain angular range (more light with active illumination; less light with passive illumination). The volume hologram with lens function is only efficient within a specific angular range. A strong change in intensity is received by the sensor device for the selection area. Adjacent selection areas receive no or only slight changes in intensity at the sensor device because the angular range is not efficient for them.

Claims

1. Detector system having a waveguide (2) that comprises a transparent base body (6) having a front (7) and a rear (8), a display device (3) that shows multiple selection regions (A1, A2, A3, A4, A5, A6) in such a way that they can be seen in a display region (9) of the base body (6) when the front (7) is viewed, a sensor device (4) that comprises an assigned sensor section (41-46) for each selection region (A1-A6), and a control device (5), wherein the base body (6) includes a diffractive element in the display region (9) and a decoupling region (10) that is spaced apart from the display region (9) and comprises an assigned decoupling section (101-106) for each selection region (A1-A6), wherein at least a portion of radiation that is incident on the diffractive element (11) in the display region (9) via the front (7) is deflected by means of the diffractive element (11) on the basis of the selection region (A1-A6) in such a way that the deflected portion propagates as coupled-in radiation in the base body (6) by reflection as far as the decoupling region (10) and is incident on the assigned decoupling section (101-106) of the decoupling region (10), wherein the decoupling region (10) decouples at least a portion of the coupled-in radiation that is incident on it from the base body (6) in such a way that the portion decoupled by a decoupling section (101-106) is incident on the assigned sensor section (41-46) of the sensor device (4), which section continuously measures the intensity of the incident radiation and supplies it to the control device (5), the control device (5) taking a change in intensity caused by an object (14) being positioned in front of the front (7) of the base body (6) and in front of a selection region of the display region (9) as a basis for determining whether the selection region has been selected.

2. Detector system according to Claim 1, wherein the diffractive element is in the form of a volume hologram.

3. Detector system according to one of the above claims, wherein the diffractive element (9) comprises a lens element function.

4. Detector system according to Claim 3, wherein the lens element function of the diffractive element (9) is designed in such a way that the coupled-in radiation propagates in the base body (6) as a parallel pencil of rays.

5. Detector system according to one of the above claims, wherein the decoupling region comprises a volume hologram.

6. Detector system according to one of the above claims, wherein the decoupling region comprises a lens element function.

7. Detector system according to one of the above claims, wherein the deflection by means of the diffractive element (11) on the basis of the selection region (A1-A6) differs by different propagation angles within the transparent base body (6) and / or different deflected wavelengths.

8. Detector system according to one of the above claims, wherein the diffractive element for each selection region (A1-A6) comprises a coupling section (91-96) that has a smaller two-dimensional extent than the assigned selection region (A1-A6).

9. Detector system according to one of the above claims, wherein there is provision for an illumination device that actively illuminates the object (14) to be positioned in front of the front (7).

10. Detector system according to Claim 9, wherein the illumination device is designed in such a way that it illuminates the object (14) from the base body (6).

11. Detector system according to one of the above claims, wherein the control device (5) takes the measured intensity as a basis for ascertaining the distance of the object (14) from the front (7).

12. Detector system according to one of the above claims, wherein the control device takes the determined selection region as a basis for controlling the display device (3) in such a way that the display device (3) changes its display, and / or changes the value of a measurement parameter and output parameter.