A projector for illuminating a holographic projection surface of a vehicle, a projection device for the vehicle, and a method for operating the projector.

Abstract

Projector for illuminating a holographic projection surface of a vehicle, projection device for a vehicle, and method for operating the projector. The present invention relates to a projector (100) for illuminating a holographic projection surface (105) of a vehicle, wherein the projector (100) has a light source (110) for outputting a split beam (115) and at least one filter element (120) tiltable relative to an optical axis, the filter element being configured to at least filter the split beam (115) such that the spectral component (125) of the split beam (115) is transmitted in order to illuminate the holographic projection surface (105).

Description

Technical Field

[0001] This invention is based on a projector for illuminating a holographic projection surface of a vehicle, a projection device for the vehicle, and a method for operating the projector, according to the preamble of the independent claim. Computer programs are also the subject of this invention. Background Technology

[0002] DE 101 36 786 B4 describes a holographic screen for front projection, a projection system, and a method for projecting images. Summary of the Invention

[0003] Against this backdrop, the present invention proposes a projector for illuminating a holographic projection surface of a vehicle, a projection device for a vehicle, and a method for operating the projector, as described in the independent claim, along with a control device for using the method and a corresponding computer program. Advantageous modifications and improvements to the device described in the independent claim are possible through the measures listed in the dependent claims.

[0004] The proposed scheme advantageously creates the possibility of adapting the projector unit spectrally to the hologram used as the projection surface. This advantageously balances deviations caused by environmental influences and / or manufacturing tolerances.

[0005] A projector for illuminating a holographic projection surface of a vehicle is proposed. The projector has a light source for outputting a split beam and at least one filter element tilted relative to the optical axis. The filter element is configured to at least filter the split beam, such that the spectral components of the split beam are transmitted to illuminate the holographic projection surface.

[0006] A projector can be used in this, for example, a projection device. The holographic projection surface can be shaped as transparently as a scheibe. The light source can be implemented as a light-emitting diode, for example. The beam splitter can include, for example, red, green, or blue light, such that the beam splitter can have a predetermined, defined wavelength. The optical axis can be arranged, for example, along the beam splitter, such that the beam splitter can be incident on a filter element. Thus, the spectral components required to illuminate the projection surface can be advantageously transmitted. The filter element can be arranged such that the normal of the filter element is rotated out of the optical axis by tilting. The beam splitter can therefore be incident obliquely on the filter element in the tilted state, and, for example, take a longer path through the material of the filter element than when the filter element is not tilted relative to the beam splitter.

[0007] According to one embodiment, the filter element can be shaped to deflect the non-transmitted component of the split beam. This means that the non-transmitted component of the split beam is advantageously reflected as a reflected split beam component in the direction of the light source. Alternatively, it is conceivable that the reflected split beam component is directed into an optical trap.

[0008] Furthermore, the filter element can be tilted within a tilt angle range of 0° to 35°. Here, the filter element can have tilt characteristics related to the tilt angle. This means that, depending on the tilt angle, the spectrum of the projector can be advantageously adapted to the hologram to be projected, in such a way that the spectral range of the split beam is shifted by the tilted filter element.

[0009] According to one embodiment, the filtering element can be shaped as a bandpass filter or an interference filter. Advantageously, a large amount of unused light transmitted through the holographic projection surface can be filtered in the projector, thereby reducing the component transmitted through the projection surface. This reduces unintentional inherent interference light and thus, for example, avoids glare to the viewer or unintentional blurring of the environment during transmission.

[0010] Furthermore, the projector may have at least one additional light source for outputting at least one additional beam. The beams and the additional beams may have different wavelengths. The projector may, in particular, have at least one additional filter element that is tiltable relative to an additional optical axis. The projector advantageously has multiple light sources that output red, green, and blue light. For example, the light sources may be arranged linearly relative to each other in the projector. Furthermore, each of the light sources may have its own filter element, which may be similarly shaped, for example.

[0011] According to one embodiment, the light source and additionally or alternatively, other light sources can be shaped as broadband light sources, particularly wherein the light source and additionally or alternatively, other light sources can be configured to output light with a beam splitter having a bandwidth of 20 nm to 30 nm and at least one additional beam splitter. The light source can advantageously be shaped as an LED light source.

[0012] Furthermore, the projector can be configured as an optical device for imprinting a light pattern onto a light beam or at least one split beam and additionally or alternatively for directing at least one split beam onto a projection surface. The projector may advantageously have, for example, a digital light processing (DLP) chip arranged within the optical device. The light beam may include at least one or more split beams. The optical device can be configured, for example, to focus the light beam and additionally or alternatively to scatter the light beam to project an image pre-given by the DLP chip onto the projection surface.

[0013] Furthermore, a projection device for a vehicle is proposed, the projection device having at least one holographic projection surface. In particular, the holographic projection surface is configured to project at least one image onto one of a plurality of predetermined spatial regions according to the wavelength of a beam of light illuminating the holographic projection surface. The projection device further includes a projector for illuminating the holographic projection surface, as in the aforementioned variant.

[0014] The projection device can be implemented, for example, in a vehicle, such as a passenger car. It is also conceivable to implement the projection device in a multi-purpose vehicle or a heavy-duty truck. For example, the predetermined spatial area can be referred to as the eye-tracking range or display area. This means that, for example, the driver of the vehicle can only see the projection when their eyes are within the spatial area. Outside the spatial area, the projection surface can advantageously appear transparent.

[0015] According to one embodiment, the projection surface can be integrated into or disposed on the window panel of the vehicle. The projection can advantageously be projected onto the side window panel, front window panel, or rear window panel of the vehicle.

[0016] According to one embodiment, the projection device may have an additional holographic projection surface, particularly wherein the additional holographic projection surface can be configured to project at least one additional image onto one of a plurality of predetermined spatial regions according to the wavelength of the beam illuminating the additional holographic projection surface. Advantageously, this allows switching between different projection surfaces by means of tilting at least one filter element.

[0017] Furthermore, a method for operating the projector in one of the aforementioned variants is proposed. Here, the method includes the steps of outputting at least one beam splitter and filtering the beam splitter, such that the spectral components of the beam splitter are transmitted to illuminate the holographic projection surface.

[0018] This method can be advantageously implemented in the projector of the previously mentioned variant.

[0019] This method can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, such as in a control device.

[0020] The solution proposed herein further implements a control device configured to perform, manipulate, or implement the steps of a variation of the method proposed herein within a corresponding device. The objective upon which this invention is based can also be solved quickly and efficiently through this embodiment of the invention in the form of a control device.

[0021] Therefore, the control device may have at least one computing 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 outputting control signals to the actuator, and / or at least one communication interface for reading or outputting data embedded in a communication protocol. The computing unit may be, for example, a signal processor, a microcontroller, etc., and the storage unit may be flash memory, EEPROM, or magnetic storage. The communication interface may be configured for wireless and / or wired data reading or output, wherein a communication interface capable of reading or outputting wired data may, for example, read the data electrically or optically from a corresponding data transmission line or output the data to a corresponding data transmission line.

[0022] Currently, a control device can be understood as an electrical device that processes sensor signals and outputs control and / or data signals accordingly. The control device may have an interface, which can be constructed in hardware and / or software. In the case of a hardware construction, the interface may, for example, be part of a so-called system ASIC that contains various functions of the control device. However, it is also possible that the interface is its own integrated circuit or at least partially composed of discrete components. In the case of a software construction, the interface may be a software module, which, for example, exists on a microcontroller among other software modules.

[0023] It is also advantageous to have a computer program product or computer program with program code, which can be stored on a machine-readable carrier or storage medium, such as semiconductor memory, hard disk memory or optical memory, and is especially used to perform, implement and / or manipulate the steps of the method according to one of the above embodiments when the program product or program is executed on a computer or device. Attached Figure Description

[0024] Embodiments of the proposed solution are shown in the accompanying drawings and will be described in more detail in the following description. Wherein:

[0025] Figure 1 A schematic cross-sectional view of a projector according to one embodiment is shown;

[0026] Figure 2a A schematic diagram of a projection device according to one embodiment is shown;

[0027] Figure 2b A wavelength efficiency diagram according to one embodiment is shown;

[0028] Figure 3 A schematic diagram showing one embodiment of the projection device;

[0029] Figure 4A schematic diagram showing one embodiment of the projection device;

[0030] Figure 5 A schematic diagram showing one embodiment of the projection device;

[0031] Figure 6 A schematic diagram showing one embodiment of the projection device;

[0032] Figure 7 A schematic diagram showing one embodiment of the projection device;

[0033] Figure 8 A schematic diagram showing one embodiment of the projection device;

[0034] Figure 9 A schematic diagram showing one embodiment of a projection device in a vehicle;

[0035] Figure 10 A wavelength diagram according to one embodiment is shown;

[0036] Figure 11 A flowchart illustrating a method for operating a projector according to one embodiment is shown; and

[0037] Figure 12 A block diagram of a control device according to one embodiment is shown. Detailed Implementation

[0038] In the following description of advantageous embodiments of the invention, the same or similar reference numerals are used for elements shown in different figures and functioning similarly, wherein repeated descriptions of these elements are omitted.

[0039] Figure 1 A schematic cross-sectional view of a projector 100 according to one embodiment is shown. Here, the projector 100 is implemented, for example, in a projection device as described in one of the following figures. Here, the projector 100 is configured to illuminate a holographic projection surface 105 of a vehicle. Here, the projector 100 has a light source 110 configured to output a split beam 115. Furthermore, the projector 100 has a filter element 120 tiltable relative to the optical axis, the filter element 120 being configured to filter at least the split beam 115, such that the spectral component 125 of the split beam 115 is transmitted to illuminate the holographic projection surface 105.

[0040] The projection surface 105 is integrated into or disposed on the window panel of a vehicle, for example. This means that, according to this embodiment, the projection surface 105 is shaped to be transparent. The light source 110 is shaped as a broadband light source 110, for example, shaped as a direct-emitting LED, which outputs light from at least one beam 115 having a bandwidth of 20 nm to 30 nm. Optionally, the projector 100 further has at least one additional light source 130, which is configured to output at least one additional beam 135. According to this embodiment, the beam 115 and the additional beam 135 have different wavelengths from each other. Furthermore, the projector 100 has at least one additional filter element 140 that is tiltable relative to an additional optical axis. Accordingly, according to this embodiment, the additional light source 130 is also shaped and configured as a broadband light source to output light from at least one additional beam 135 having a bandwidth of 20 nm to 30 nm. Generally, according to this embodiment, the projector has an additional light source 145, which is shaped in principle like the other light sources 110 and 130. In general, the projector 100 is shaped, for example, as an RGB projector. Here, each of the light sources 110, 130, and 145 has a cooling body 150, which, according to this embodiment, has heat sinks.

[0041] According to this embodiment, filter element 120 is shaped to deflect the non-transmitted component of the split beam 115. According to this embodiment, the non-transmitted component is not shown here. The non-transmitted component is reflected, for example, at filter element 120 in the direction of the light source 110, or deflected, for example, into an optical trap. Filter element 120 and / or additional filter element 140 are here tilted within a tilt angle range of 0° and 35° and have tilt characteristics related to the tilt angle. Thus, for example, the transmission curves of the one or more filter elements 120, 140 are shifted to shift the spectral range of the projector light emitted as beam 155. According to this embodiment, at least filter element 120 is shaped as a bandpass filter or an interference filter.

[0042] The projector 100 optionally includes an optical device 160 configured to, for example, imprint a light pattern onto a light beam 155 by means of a digital light processing chip 165 (DLP) and / or to redirect at least one split beam 115, 135 of the light beam 155 onto a projection surface 105. According to this embodiment, the DLP chip 165 is connected to an additional cooling element 166. According to this embodiment, the projector 100 or the optical device 160 may optionally include a projection lens 175, which may optionally be removable or at least adjustable.

[0043] In other words, the proposed scheme here provides a wavelength-adaptive projection for a holographic projection surface 105, which is also referred to as a display, for example. More precisely, the projector structure of the projector 100 is shown here according to a DLP projector having integrated bandpass filters as filter elements 120, 140. For this purpose, at least one rotatable filter element 120, 140 is integrated into the optical path of the projector 100 as a bandpass filter for each color of the beam 155 to realize a hologram. Here, the projector 100 works with light sources 110, 130, each having a spectral bandwidth wider than the spectral bandwidth of the hologram used as the projection surface 105. The filter elements 120, 140 in the optical path of the projector 100 filter the light so that the projector 100 emits the desired component 125 of the light available through the light sources 110, 130, 145. Thus, only the desired component is projected onto the holographic projection surface 105. By changing the positions of the bandpass filters 120 and 140, the transmission curves of the filter elements 120 and 140 are shifted. Consequently, the spectral range of the emitted projector light 155 is also shifted. In this way, the spectrum of the projector 100 is adapted to the hologram. Through spectral adaptation, the spectrum of the projector 100 is ideally adapted to the hologram and, for example, to the hologram's maximum efficiency. Furthermore, spectral shifts in at least one light source 110, 130, 145 due to operating mode or environmental influences are balanced. Additionally, according to this embodiment, spectral shifts caused by manufacturing tolerances are balanced. Furthermore, the solution presented herein, according to this embodiment, allows switching between transmissive and reflective displays, as well as switching between multiple spatial regions and / or multiple projection surfaces.

[0044] Therefore, according to this embodiment, each of the light sources 110, 130, and 145 of the projector 100 is equipped with a filter element 120, 140, which transmits the spectral components of the corresponding light source 110, 130, and 145, respectively, which are used by the hologram. Each of the filter elements 120 and 140 transmits the required spectral component and filters out the remaining components. This relates to an interference filter. Here, the unused components are reflected back to the light sources 110, 130, and 145, or alternatively, they are redirected into the light trap when the filter elements 120 and 140 are tilted. The spectral components used are first superimposed in the projector 100 by a dichroic mirror, and then illuminated by another optical element, referred to here as an optical device 160 such as a lens or microlens array, as an imager chip (DLP chip 165) for imaging, and then focused onto the projection surface 105 by means of a projection lens 175. The projector 100 based on the DLP chip 165 shown schematically here can be considered as a possible implementation variant. The bandpass filtering principle of the proposed light sources 110, 130, and 145 can also be applied to other projector variants, such as the LCD or LCoS-based projector 100.

[0045] In general, projector 100 can be used in holographic projection devices, which can be implemented, for example, with rear projection or front projection. Such projection devices are conceivable, for example, in the automotive or consumer applications. According to this embodiment, holographic projection is suitable for use with a transparent projection surface 105, for example, implemented in a window panel. Here, projector 100 can optionally be used for, for example, every type of holographic projection based on LED light.

[0046] Figure 2a A schematic diagram of a projection device 200 according to one embodiment is shown. The projection device 200 is, for example, represented as a holographic display system having a projector 100 and a holographic projection surface 105, and having at least one holographic projection surface 105, the holographic projection surface being, for example, corresponding to... Figure 1 The projection surface is drawn in the image. According to this embodiment, the basic principle of the projection device 200 is shown.

[0047] The holographic projection surface 105 is configured to project at least one image onto a predetermined spatial region 205 according to the wavelength of the beam 155 illuminating the holographic projection surface 105. According to this embodiment, the beam 155 strikes the projection surface 105. The projection device 200 further has, as... Figure 1 The projector 100 described herein is configured to illuminate a holographic projection surface 105. According to this embodiment, the projection surface 105 is integrated into a vehicle window panel, or, for example, disposed on such a window panel. Here, the projection surface 105 is, for example, implemented or can be implemented as a holographic thin film.

[0048] According to this embodiment, generally speaking, a beam 155 is output by the projector 100 to project an image onto a projection surface 105. The beam 155 is further reflected at the projection surface 105 into a spatial region 205, which is also referred to, for example, as the eyebox or display area. If the user 210 or their field of view is, for example, located within the spatial region 205, the user sees the image on the projection surface 105. According to an alternative embodiment, the projection device 200 has a further projection surface (not shown here) configured to project at least one additional image onto one of a plurality of predetermined spatial regions 205 according to the wavelength of the beam illuminating the additional holographic projection surface.

[0049] In other words, according to this embodiment, the basic principle of a holographic projection system having a transparent projection surface 105, also referred to as a display, is shown. This holographic projection system is referred to herein as a projection device 200. Here, the projector 100 projects an image onto the holographic projection surface 105, which scatters light from a beam of light 155 in the direction of a defined spatial region 205. The holographic projection surface 105 is, for example, composed of a hologram and, for example, a glass pane. The hologram may also be embedded in a composite glass pane. Here, the hologram is, for example, wavelength-selective depending on the light beam 155 incident from the projector 100 and angle-selective depending on the angle of incidence from the projector 100. Due to the angle and wavelength selectivity of the hologram, it is transparent to other incident angles and wavelength ranges. Through these characteristics, the hologram appears transparent to the viewer or user 210. For light incident from the projector 100, the hologram or projection surface 105 acts as a scattering surface, scattering the incident light into the spatial region 205. Projector 100 projects a clear image onto projection surface 105. By scattering into spatial region 205, the image is visible on projection surface 105 to user 210 located at eye movement range 205 and is superimposed on the background due to the transparency of projection surface 105.

[0050] Therefore, according to this embodiment, a holographic display system with a transparent projection surface 105 is realized, wherein the projector 100 is spectrally adapted to the hologram referred to as the projection surface 105. This, for example, balances deviations caused by manufacturing tolerances or environmental influences. This avoids unwanted spectral components transmitted at the holographic projection surface 105. Furthermore, the active adaptation of at least one filter element 120, 140 of the spectral characteristics during operation enables new display concepts, such as the switching between reflective and transmissive displays as proposed according to this embodiment.

[0051] In other words, the scheme presented here further implements a display system referred to herein as projection device 200, which has a projector 100 that may be called a projector unit. According to this embodiment, projection device 200 is spectrally adjustable and thus adaptable to projection surface 105. Projection surface 105 contains a hologram or holographic layer that is spectrally wavelength sensitive and therefore effective only for a specific wavelength range. Such efficiency curves are exemplarily shown in the following figures for two different holograms.

[0052] Broader light sources, such as direct-emitting LEDs, are used as the light source in the projector 100 of the projection device 200. These light sources contain a bandwidth of 20 nm to 30 nm. Since the hologram has only a spectral sensitivity range of, for example, 10 nm, the remaining components of the light source remain unused and are transmitted through the hologram. For example, this unused portion may, for instance, unintentionally illuminate other surfaces behind the projection surface 105, or directly dazzle the observer.

[0053] By filtering, according to this embodiment, the projector 100 emits only the wavelength range effectively processed by the hologram. This significantly reduces or eliminates the transmitted and interfering components at the hologram. This means that the bandpass filter of the projector 100 is adjustable in its angular position. Here, the individual bandpass filters in the optical path are variable in their tilt relative to the optical axis and can be adjusted, for example, within an angle range of 0° to 30°, as already... Figure 1 As already described. If such an interference filter changes its angle relative to the transmitted light, the behavior shown in one of the following figures is obtained. The transmission curve of the bandpass filter shifts with wavelength here. The spectral transmission range of the light source can be adjusted by rotating the bandpass filter and, according to this embodiment, fixed when the desired behavior is achieved.

[0054] Due to tolerances in hologram construction and system structure, such as positional tolerances, the maximum value of the hologram's efficiency curve is not always precisely at the desired wavelength, but is directionally variable. An adjustable bandpass filter in projector 100 allows the light 155 emitted by projector 100 to be spectrally matched to and calibrated for the efficiency of the hologram in projection surface 105. This provides the possibility of balancing tolerances caused by manufacturing processes.

[0055] According to an alternative embodiment, the bandpass filter in the projector 100 is controllable and can be shaped in an adjustable manner in its tilt by means of an active mechanical device. This allows for dynamic adaptation to the projection device 200. Furthermore, the spectral wavelength range of the projection can be adapted to the operating mode. This, for example, enables the equalization of wavelength shifts in the efficiency curve of the hologram caused by external influences, such as variations in lifespan or temperature range.

[0056] Figure 2b A wavelength efficiency graph 250 is shown according to one embodiment. According to one embodiment, wavelength efficiency graph 250 represents, for example,... Figure 2a The wavelength efficiency of at least one beam of the projection device described herein. According to this embodiment, the x-axis 255 of the wavelength efficiency graph 250 represents the wavelength of at least one beam in nm. The y-axis 260 of the wavelength efficiency graph 250 represents the efficiency in % (percentage). According to this embodiment, the wavelength efficiency graph 250 thus shows a first efficiency curve 265 and a second efficiency curve 270 that differ from each other according to this embodiment. Efficiency curves 265 and 270 here represent two holograms parameterized differently from each other.

[0057] The precise curve variations of efficiency curves 265 and 270 are determined, for example, by the material properties of the hologram, such as its refractive index modulation, thickness, and the recording parameters used when constructing the hologram. The two curves illustrate a spectral sensitivity range, for example, from 10 nm to 20 nm half-width.

[0058] In other words, a hologram has at least one spectral efficiency curve 265, 270 due to its wavelength selectivity. The peak wavelengths of the spectral efficiency curves 265, 270 can be adjusted by the recording configuration of the hologram and are very precise and largely freely definable. For incident light located outside these efficiency curves 265, 270, the hologram has no effect and the light is transmitted. The spectral widths of the efficiency curves 265, 270 are in the range of, for example, 10 nm to 20 nm, depending on the material properties and the establishment of the hologram. The light from these sources can be used very efficiently, for example, in a projector, if a light source providing very narrow bandgap light is used. Instead of lasers, light sources with a wider bandwidth, such as LEDs, can be used. Due to the wavelength selectivity of the hologram, a major portion of the projector light remains unused by the hologram and is transmitted at the hologram. This transmitted light component typically acts as a interference component and can lead to undesirable effects, such as unintentional blurred projections on surfaces behind the actual projection surface, or dazzling the observer on the side of the projection surface opposite the projector. By means of the scheme proposed herein, light emitted from at least one light source is filtered by a filter element, preventing interfering components from reaching the projection surface and avoiding the aforementioned problems. Manufactured to a degree, for example, the peak wavelength of an LED is within a specific range in a scattered manner and can vary, for example, by 12 nm. This is achieved through bandpass filtering: the wavelength range emitted by the projector then also coincides with the efficiency curves 265 and 270 of the hologram, because the bandpass filter again filters out the desired range from the broader spectrum of the shifted light source. In this way, the wavelength tolerance of the light source can be compensated. According to this embodiment, this effect works even when the wavelength of the light source changes according to the operating mode of the display system. For example, the temperature of the LED sometimes has a strong influence on the peak wavelength of the emitted light. Therefore, by using bandpass filtering, the light emitted by the projector becomes more robust relative to temperature fluctuations.

[0059] When dimming a projector to adapt the display to a lower brightness, for example, by reducing the operating current of the light source, the amount of light generated is reduced. This reduction in current also results in a wavelength shift of the peak wavelength, which can be equalized using the proposed measures.

[0060] Figure 3 A schematic diagram illustrating one embodiment of the projection device 200 is shown. The projection device 200 shown here corresponds to... Figure 2a The projection device 200 described herein, and the projector 100 shown corresponds to Figure 1The projector 100 is described in the figure. According to this embodiment, the projection device 200 is shaped such that the unused spectral component 300 of the beam 155 passes through or radiates across the projection surface 105. The used spectral component 125 is reflected at the projection surface into the spatial region 205. According to this embodiment, the projection device 200 is generally represented as a holographic display system having a projector 100 and a holographic projection surface 105, taking into account the unused spectral component 300.

[0061] Figure 4 A schematic diagram illustrating one embodiment of a projection device 200 is shown. The projection device 200 shown herein is similar to... Figure 3 The projection device 200 described herein, in addition to projection surface 105, has only one additional projection surface 400, which is configured to project at least one additional image onto one of a plurality of predetermined spatial regions 205 according to the wavelength of the light beam 155 or split beam illuminating the additional holographic projection surface 400. This means that, according to this embodiment, at least one additional spectral component 405 is reflected into the spatial region 205 by the additional projection surface 400. According to this embodiment, projection surfaces 105, 400 are in contact with each other. According to this embodiment, the two projection surfaces 105, 400 are shaped into a reflective hologram. In general, according to this embodiment, the projection device 200 is represented as a holographic display system having an adaptable wavelength range for switching between two separate spatial regions 205.

[0062] In other words, a projection device 200 is implemented such that the spectral adaptability of the projector 100 allows it to use the holographic functions of different holograms depending on the operating state. Here, the projector 100 is aligned with projection surfaces 105 and 400, which are implemented by at least one hologram, each hologram having two different holographic functions for each color of light. The efficiency curves of the colors of light are located in different spectral ranges. Therefore, it is possible to selectively respond to one of the two holograms using a corresponding color of light by adapting the spectrum of the corresponding color to the efficiency curve of the corresponding holographic function. For example, different holographic functions can be implemented in the same holographic layer. Alternatively, according to this embodiment, the two projection surfaces 105 and 400 having corresponding functions are superimposed.

[0063] According to this embodiment, the projection surface 105 selectively acts, for example, within a first wavelength range and thus performs the optical function of generating one of the spatial regions 205 of the scattering surface. A second optical function of generating the other of the spatial regions 205 is achieved by the additional projection surface 400, whose efficiency lies in a different wavelength range. For example, this additional wavelength range represents a different spectral component 405. Switching between spatial regions 205 can be performed by switching between wavelength ranges. In the intermediate region where the spectral bandwidth of the projector 100 is adjusted such that the spectral bandwidth overlaps with the two efficiency curves of the corresponding hologram, light 155 is divided onto the two spatial regions 205 and is visible from both spatial regions 205.

[0064] According to this embodiment, different holographic functions can be implemented either in multiple stacked projection surfaces 105, 400, or in a single holographic layer, which thus carries two different holographic functions for each color of light. Here, the display can be implemented via front projection or rear projection. The optical function of the hologram is implemented as a reflective hologram in the case of front projection and as a transmissive hologram in the case of rear projection.

[0065] Figure 5 A schematic diagram illustrating one embodiment of the projection device 200 is shown. The projection device 200 shown herein is similar to... Figure 4 The projection device 200 described herein. According to this embodiment, the projector 100 shown corresponds to... Figure 1 The projector 100 described herein. Only the position of the spatial region 205 relative to... Figure 4 The spatial regions 205 shown are different. According to this embodiment, the spatial regions 205 intersect, such that the first region 500 is arranged within the second region 505. This means that, for example, the first projection within the first region 500 is visible and is smaller than the second projection in the second region 505. According to this embodiment, an image projected onto the projection surface 105 is visible in the first region 500, and another image projected onto the other projection surface 500 is visible in the second region 505. According to this embodiment, the two projection surfaces 105, 400 are formed into a reflective hologram.

[0066] According to this embodiment, two holographic functions each generate one of a plurality of spatial regions 205. Here, one holographic function implements a smaller region 500, and the other holographic function implements a larger region 505. The projection surface 105 implementing the first region 500 optionally produces a brighter image compared to the second region 505 by concentrating available light 155 in the first region 500. A holographic function in a second wavelength range implements the second region 505, which less restricts the display area from which the display is observed. Such a system can be used to restrict the spatial region 205 in particularly bright environments to facilitate brightness. According to this embodiment, at least one of the projection surfaces 105, 400 can be used, for example, in a vehicle window panel to ensure readability even in high ambient light, while widening the viewing area in low ambient light.

[0067] In general, according to this embodiment, the projection device 200 is represented as a holographic display system having an adaptable wavelength range for switching between two spatial regions 205 of different sizes.

[0068] Figure 6 A schematic diagram illustrating one embodiment of the projection device 200 is shown. The projection device 200 shown here is similar to... Figures 3 to 5 One of the projection devices 200 described herein. According to this embodiment, the projector 100 shown corresponds to... Figure 1 The projector 100 is described in the text. According to this embodiment, projection surfaces 105 and 400 are arranged adjacent to each other. Only with… Figure 5 In contrast, the regions 500 and 505 of spatial region 205 are arranged separately on opposite sides of projection surfaces 105 and 400. This means that, according to this embodiment, projection surface 105 is also shaped as a reflective hologram as described above. According to this embodiment, the additional projection surface 400 is shaped as a transmission hologram, such that additional spectral components 405 of the beam 155 are transmitted through projection surfaces 105 and 400 to display an additional image in the second region 505. In general, according to this embodiment, the projection device 200 is represented as a holographic display system with an adaptable wavelength range for switching between display in reflection and display in transmission.

[0069] According to this embodiment, switching is performed between the display in reflection in the first region 500 and the display in transmission in the second region 505 by switching between two wavelength ranges of the projector 100. Here, the holographic function of the reflection hologram for red, green, and blue and the holographic function of the transmission hologram for red, green, and blue can be implemented either in a common holographic layer or in two separate holographic layers.

[0070] Figure 7A schematic diagram illustrating one embodiment of the projection device 200 is shown. The projection device 200 shown herein is similar to... Figure 6 The projection device 200 described herein. According to this embodiment, the projector 100 shown corresponds to... Figure 1 The projector 100 described herein. The only difference is that, according to this embodiment, the projection device 200 has a single projection surface 105 that reflects spectral component 125 into one of the spatial regions 205 and transmits another spectral component 405 into another of the spatial regions 205. According to this embodiment, this can be achieved by switching and / or tilting the filter element 120. In general, according to this embodiment, the projection device 200 is represented as a holographic display system with an adaptable wavelength range for switching between display in reflection and display in transmission.

[0071] The proposed solution here reduces, for example, the manufacturing cost of the projection device 200. When implemented in two separate holographic layers, the advantage lies in avoiding cross-coupling. For example, such cross-coupling is expressed as the holographic function of the additional projection surface 400 also unintentionally acting within the wavelength range of the projection surface 105.

[0072] According to this embodiment, at least one filter element 120 in the projector 100 is indicated in two different positions. In the first position, the wavelength range of the transmission is effective for the holographic function of the reflection hologram. This holographic function is written into the holographic projection surface 105 for all three colors. If the position of at least one filter element 120 is changed to a second configuration, the wavelength range of all colors used by the projector 100 shifts. The light emitted by the projector 100 is now outside the efficiency curve of the reflection hologram in the spectrum, but within the efficiency curve of the transmission hologram for each color. The optical hologram functions represent scattering surfaces that create spatial regions from which the viewer perceives the image content projected on the projection surface 105. The wavelengths can be adapted to the efficiency range of the transmission or reflection hologram functions individually and independently. Thus, for example, it is possible to achieve a mixed color including red and green display inward (meaning, for example, in the interior space of a vehicle), and simultaneously achieve a blue display with different image content outward. If at least one filter element 120 is located in the middle position between the two positions shown, the wavelength range used by the projector 100 overlaps with the efficiency curves of the two holographic functions, and full-color display is performed simultaneously outward and inward.

[0073] Figure 8 A schematic diagram illustrating one embodiment of the projection device 200 is shown. The projection device 200 shown herein is at least similar to... Figure 7 The projection device 200 described herein. According to this embodiment, the projector 100 shown corresponds to... Figure 1The projector 100 described herein. (And...) Figure 7 compared to, Figure 8 The projection device 200 is shown differently because it has a projection surface 105 and an additional projection surface 400, both of which represent images in the same spatial region 205. Here, according to this embodiment, the two projection surfaces 105 and 400 are implemented as reflective holograms that interact only with different wavelengths.

[0074] According to this embodiment, a projection device is shown, which projects onto different projection surfaces 105, 400 by means of a spectrally adaptable projector 100 depending on its operating state. According to this embodiment, the projector 100 can shift the spectrum emitted by each color of light by adapting the position of at least one bandpass filter. This allows for the radiation of a first wavelength range or alternatively, a second wavelength range different from it, adapted to a first holographic function and a second holographic function. Here, the first holographic function is implemented in the holographic projection surface 105 and implements the scattering function of light 155 for the first wavelength range, meaning the scattering function of the spectral components 125 for the light beam 155. This creates a spatial region 205 for the observer to perceive the image content displayed on the projection surface 105. If the spectral range of the projector 100 is shifted to the second wavelength range, the incident light 155 is transmitted through the projection surface 105, and the holographic function in the projection surface 105 is inactive. When projected onto another projection surface 400, this is sensitive to the second wavelength range, meaning to the other spectral component 405. This means that the efficiency curve of the hologram in the other projection surface 400 coincides with the spectrum of the second wavelength range. Thus, the optical function of the other projection surface 400 comes into play and, for example, through scattering, generates a spatial region 205 for the observer, who ultimately perceives the image content on the other projection surface 400 from this eye-tracking range. The spatial regions 205 of the different projection surfaces 105, 400 may alternatively be spatially different. Furthermore, one or both of the projection surfaces 105, 400 may alternatively be implemented as a transmission display. Furthermore, the other projection surface 400 may optionally not be transparent, but may also be implemented, for example, as an opaque surface. Alternatively, the other projection surface 400 is not necessarily holographically implemented and may be implemented, for example, as a conventional scattering surface, such as a scattering surface implementing Lambertian radiation.

[0075] According to this embodiment, the switching between the two projection surfaces 105, 400 is performed individually and / or independently of the colors of the projector 100. If the two projection surfaces 105, 400 are spatially distant from each other such that the depth of field of the projector 100 is no longer sufficient to project a sufficient image sharpness onto the two surfaces 105, 400, the projector 100 may optionally be actively adjusted using a focusable lens.

[0076] In general, according to this embodiment, the projection device 200 is represented as a holographic display system having an adaptable wavelength range for switching between two different projection surfaces 105, 400.

[0077] Figure 9 A schematic diagram illustrating one embodiment of a projection device 200 in a vehicle 900 is shown. According to this embodiment, the projection device 200 depicted herein is similar to... Figure 2a And / or at least one of the projection devices 200 described in 3 to 8. According to this embodiment, the projection device 200 has a holographic projection surface 105 and an additional holographic projection surface 400. According to this embodiment, the projection surfaces 105, 400 are arranged in or integrated into a window panel 905. According to this embodiment, the window panel 905 is arranged at a door 910, such that, according to this embodiment, the window panel 905 can be identified as a side window of the vehicle 900. In addition to the aforementioned projection device 200, according to this embodiment, the projection device 200 has a mirror element 915 configured to reflect a light beam output by the projector 100 onto the projection surfaces 105, 400. According to this embodiment, the projector 100 and the mirror element 915 are arranged in the top region of the vehicle 900, such that, for example, the driver of the vehicle 900 remains undisturbed and / or glare-free.

[0078] Such a projection device 200 is configured, for example, to enable switching between internal and external displays on a display in the side window panel 905 of the vehicle 900.

[0079] In other words, according to this embodiment, the projection device 200 is shown for projecting image content onto the side window panel 905, wherein the image content is visible from the interior or exterior of the vehicle 900 depending on the position of the one or more filter elements.

[0080] Figure 10 A wavelength diagram 1000 is shown according to one embodiment. The x-axis 1005 of the wavelength diagram 1000 represents wavelength in nm, and the y-axis 1010 of the wavelength diagram 1000 represents intensity. According to this embodiment, curve 1015 shown in the wavelength diagram 1000 represents exemplary behavior of the filter element under different tilting or tilting conditions relative to its initial position. The filter element here is, for example, as at least in… Figure 2aOr a part of the projection device described in one of 3 to 9. Therefore, the filter element is as follows: Figure 1 Implemented in the projector described in [the document].

[0081] Figure 11 A flowchart is shown for a method 1100 for operating a projector according to one embodiment. For example, method 1100 can be used to operate as follows: Figure 1 The projector described herein. Therefore, method 1100 includes an output step 1105 and a filtering step 1110. In the output step 1105, at least one beam is output. In the filtering step 1110, the beam is filtered such that the spectral components of the beam are transmitted to illuminate the holographic projection surface.

[0082] Figure 12 A block diagram of a control device 1200 according to one embodiment is shown. The control device 1200 is configured, for example, to operate or perform actions such as... Figure 11 The method described herein. According to this embodiment, the control device 1200 has an output unit 1205 and a filtering unit 1210. The output unit 1205 is configured to cause the output of at least one split beam, for example, by means of an output signal 1215 to at least one light source 110. The filtering unit 1210 is configured to cause filtering of the split beam, such that the spectral components of the split beam are transparent in order to illuminate the holographic projection surface. For this purpose, the filtering unit 1210 may optionally provide a filtering signal 1220 to the filter element 120 of the projector, in order to cause, for example, an adjustment of the position of the filter element 120.

[0083] If an embodiment includes an "and / or" association between a first feature and a second feature, it should be read as the embodiment having not only the first feature but also the second feature according to one implementation, and having either only the first feature or only the second feature according to another implementation.

Claims

1. A projector (100) for illuminating a holographic projection surface (105) of a vehicle (900), wherein the projector (100) has the following features: - a light source (110) for outputting a partial light beam (115); and - at least one filter element (120) tiltable with respect to an optical axis, which filter element is configured for at least filtering the partial light beam (115) and deflecting non-transmitted components (125) of the partial light beam (115), such that spectral components (125) of the partial light beam (115) are transmitted in order to illuminate the holographic projection surface (105), while transmitted and disturbing components at the hologram are significantly reduced or eliminated.

2. The projector (100) according to claim 1, wherein the filter element (120) is shaped in a way that it is tiltable in a range of tilt angles between 0 degrees and 35 degrees.

3. The projector (100) according to claim 2, wherein the filter element (120) has a tilt characteristic in relation to the tilt angle.

4. The projector (100) according to any one of the preceding claims 1 to 3, wherein the filter element (120) is shaped as a bandpass filter or an interference filter.

5. The projector (100) according to one of the preceding claims 1 to 3, having at least one further light source (130) for outputting at least one further partial light beam (135), wherein the partial light beam (115) and the further partial light beam (135) have different wavelengths from each other.

6. The projector (100) according to claim 5, wherein the projector (100) has at least one further filter element (140) tiltable with respect to a further optical axis.

7. The projector (100) according to claim 5, wherein the light source (110) and / or the further light source (130) is shaped as a broadband light source.

8. The projector (100) according to claim 7, wherein the light source (110) and / or the further light source (130) is configured for outputting light of the partial light beam (115) and / or the at least one further partial light beam (135) having a bandwidth of 20 nm to 30 nm.

9. The projector (100) according to any one of the preceding claims 1 to 3, having optical means (160) for imprinting a light pattern onto a light beam (155) or onto the at least one partial light beam (115, 135) and / or for diverting the at least one partial light beam (115, 135) onto the projection surface (105).

10. A projection device (200) for a vehicle (900), wherein the projection device (200) has the following features: - at least one holographic projection surface (105), wherein the holographic projection surface (105) is configured for projecting at least one image into one of a plurality of predetermined spatial regions (205) depending on a wavelength of a partial light beam (115) illuminating the holographic projection surface (105); and - at least one projector (100) according to any one of the preceding claims 1 to 9. - a projector (100) for illuminating the holographic projection surface (105) according to any one of claims 1 to 9.

11. The projection device (200) according to claim 10, wherein the projection surface (105) is integrated into or arranged on a window pane (905) of the vehicle (900).

12. The projection device (200) according to any one of claims 10 or 11, having a further holographic projection surface (400), wherein the further holographic projection surface (400) is configured for projecting at least one further image into one of a plurality of predetermined spatial regions (205) depending on a wavelength of a beamlet (115) illuminating the further holographic projection surface (400).

13. A method (1100) for operating a projector (100) according to any one of the preceding claims 1 to 9, wherein the method (1100) comprises the following steps: - outputting (1105) at least one beamlet (115); and - filtering (1110) the beamlet (115) such that a spectral component (125) of the beamlet (115) is transmitted in order to illuminate a holographic projection surface (105).

14. A control device (1200) set up for performing and / or conducting the steps (1105, 1110) of the method (1100) according to claim 13 in respective units (1205, 1210).

15. A computer program product comprising a computer program set up for performing and / or conducting the steps (1105, 1110) of the method (1100) according to claim 13 when executed on a computer.

16. A machine readable storage medium having stored thereon a computer program set up for performing and / or conducting the steps (1105, 1110) of the method (1100) according to claim 13 when executed on a computer.

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