Projecting with extended illumination area

Abstract

Projection is performed with an extended illumination area. An optical device (1) includes an imaging system (2) provided to generate multiple images distributed on an imaging plane (3). It also includes a microlens array (MLA) (9) in which microlenses are assigned to individual images (4) and provided to form a beam path (12) by projecting the individual images (4) toward a projection plane (13). An optical expander (17) is arranged between the MLA (9) and the projection plane (13) and includes an input surface (22) and at least two output surfaces (23, 26, 33). The optical expander (17) is provided to fan out and guide the beam path (12) onto the projection plane (13) such that an individual projection (14) of the individual images (4) is formed on the projection plane (13). An overall projection (15) is formed on the projection plane (13) by superimposing the individual projections (14).

Description

Technical Field

[0001] This disclosure relates to optical devices, optical apparatuses, and methods for forming an overall projection. Background Technology

[0002] Typically, the projection of moving images onto a screen relies on a projection device with a single imaging optical path. However, such devices have several drawbacks, at least when it comes to projection onto tilted or curved surfaces: for tilted surfaces, a sharp image can be achieved by tilting the object and the projection optics over a wide range. This approach is not suitable for curved projection surfaces. Furthermore, tilting increases the required installation space, which contradicts the desire for miniaturization. The increased F-number (focal length / aperture size) can be addressed by increasing the depth of focus, but this increase in F-number is usually accompanied by lower light intensity.

[0003] Therefore, for projection onto inclined and curved surfaces, the use of multi-channel optics, such as microlens arrays (MLAs), is advantageous. In this case, multiple individual images are projected onto a screen and superimposed using an MLA. The distortion of the overall projection can be compensated for by the fact that the individual images have essentially the same image content, but can be distorted relative to each other and the overall projection. On the one hand, this approach enables compact designs because the focal length of a microlens is typically smaller than that of a single-channel optics. On the other hand, multi-channel optics exhibit the necessary optical depth of focus anyway to achieve sharp projection on curved or inclined projection surfaces.

[0004] However, a drawback of multichannel optics is the relatively limited field of illumination (FOI). Here and below, FOI is defined as the width of the light cone emitted from the optics. The larger the half-cone angle of the light cone, the larger the total projection on the screen can be. Therefore, to achieve a larger projection, larger / more MLAs are needed. However, this leads to increased production costs, higher complexity, and greater alignment effort.

[0005] Therefore, the objective is to provide an optical device for forming an overall projection that presents an increased illumination area. Another objective is to provide a method for forming an overall projection with an increased illumination area.

[0006] This objective is achieved through the subject matter of the independent claims. Embodiments and developments of the optical device are defined in the dependent claims. Summary of the Invention

[0007] In one embodiment, the optical device includes an imaging system provided to generate multiple images distributed on an imaging plane.

[0008] The imaging plane is the plane in which the image is generated. The imaging system can be a transmission imaging system. This means that the imaging system can operate in transmission mode. In this case, the imaging system includes, for example, a patterned mask that exhibits a variation in its transmittance in the lateral direction. The lateral direction extends parallel to a main extension plane of the imaging plane. The patterned mask is arranged in the imaging plane. The patterned mask can be illuminated by a light source, which can be included in the imaging system. Multiple images are generated in the imaging plane through portions of the light transmitted by the patterned mask. The transmission imaging system will be described in more detail below.

[0009] The imaging system can also be an emission imaging system. In this case, the imaging system includes, for example, a self-emissive display arranged in the imaging plane. For example, a self-emissive display is a display that includes multiple light-emitting diodes (LEDs). By activating the LED group, multiple images are generated in the imaging plane.

[0010] Alternatively, the imaging system can also be a reflective imaging system. In this case, the imaging system may include a reflective structure arranged in the imaging plane. The reflective structure is illuminated by a light source, causing the light to be reflected by the reflective structure. The portion of the reflected light forms multiple images in the imaging plane.

[0011] The imaging plane extends in the lateral direction. Images can be distributed on the imaging plane in one or more lateral directions. Furthermore, images can be distributed in a regular or irregular manner on the imaging plane, meaning that the distance between adjacent images can be constant or variable. Images, or at least subsets of images, can have substantially the same content. They can all represent a version of the overall image. However, images can also differ from one another. It is possible that images are distorted relative to each other and relative to the overall image.

[0012] Optical devices also include microlens arrays (MLAs), where the microlenses of the MLA are assigned to corresponding individual images in multiple images.

[0013] An MLA can have a main extension plane parallel to the imaging plane. An MLA comprises multiple microlenses arranged in an array. The array can be regular or irregular in terms of the position of the microlenses within it.

[0014] In a preferred embodiment, each microlens is assigned to one individual image from a plurality of images. However, it is also possible to assign a group of microlenses to an individual image, or to assign each microlens to a group of individual images.

[0015] Microlenses are provided for the MLA to form corresponding channels for the beam by projecting the corresponding individual image toward the projection plane.

[0016] The projection plane is the plane on which the projection of an individual image is generated. The projection plane has a principal extension plane, which may be parallel to the principal extension plane of the imaging plane. However, in a preferred embodiment, the projection plane is inclined relative to the imaging plane. The projection plane may also not be a flat plane but a free-form surface.

[0017] Microlenses assigned to the corresponding individual images project each point of the individual image toward the projection plane. This means that each point of the image is projected toward the projection plane by means of a light beam. Thus, the projected individual images form a light beam channel.

[0018] The optical device also includes an optical expander disposed between the MLA and the projection plane. The optical expander includes an input surface facing the MLA and at least two output surfaces facing the projection plane.

[0019] Optical expanders may include materials that are transparent to light within the wavelength range of interest. Herein and hereinafter, "transparent" means at least 80% or at least 90% transparency. For example, optical expanders may include glass. In another embodiment, optical expanders may include plastics such as polycarbonate (PC), polymethyl methacrylate (PMMA), silicone, or epoxy resin.

[0020] An optical expander is positioned between the MLA and the projection plane, such that the beam path from the MLA passes through the optical expander before reaching the projection plane. The input surface of the optical expander faces the MLA and receives the beam path. The input surface can be parallel to the main extension plane of the MLA. However, the input surface of the optical expander can also be tilted relative to the MLA. At least two output surfaces of the optical expander face the projection plane. They can be parallel or tilted relative to the input surfaces. The output surfaces guide the beam path passing through the optical expander onto the projection plane.

[0021] An optical expander is provided to fan out and guide the beam channel onto the projection plane, so that an individual projection of an individual image is formed on the projection plane by the beam channel guided onto the projection plane.

[0022] This means that the optical expander extends the illumination area formed by the beam path. In other words, it provides an optical expander to guide the beam path in a direction further away from the optical axis of the optical device.

[0023] The beam path is guided onto the projection plane and forms individual projections of individual images. This means that each individual image results in an individual projection on the projection plane. Individual projections can overlap. However, at least some individual projections can also be separate from each other.

[0024] A global projection is formed on the projection plane by at least partially superimposing individual projections.

[0025] At least some points of the individual images guided and projected onto the projection plane are superimposed on the corresponding common points of the overall projection. However, there may be at least one individual projection that is not superimposed on at least another individual projection because they do not share common points with each other. It is also possible that only some points of an individual projection are superimposed on some additional points of another volume projection.

[0026] The advantage of this embodiment is that the optical device can have a small size. By assigning microlenses to individual images, the distance between the imaging plane and the projection optics (i.e., the MLA) can be reduced. This is because each microlens in the MLA has a small focal length compared to conventional projection optics. Therefore, the mounting length can be reduced, leading to system miniaturization. Although the focal length of the microlenses results in a shorter overall length of the optical device, the multiple microlenses ensure a proportional increase in image brightness.

[0027] Another advantage is that the optics can be used to generate a global projection on tilted, curved, or free-form surfaces. This is because the imaging system can be designed such that the constellation of points in individual images (each point superimposed on a corresponding common point in the global projection) varies depending on the distance of the corresponding common point in the global projection from the MLA. In other words, if the projection plane is tilted, the distortion of the global projection can be compensated for by realizing each individual image differently, although each individual image can still have substantially the same content. This means that individual images may be distorted relative to each other.

[0028] By using an optical expander, the field of view (FOI) can be advantageously expanded. Without an optical expander, MLA results in a limited FOI, and the size of the overall projection depends on the FOI. In such a system, the beam cone has a half-cone angle of approximately 10.5 degrees. By fanning out the beam path with the aid of an optical expander, the half-cone angle can be increased to, for example, 30 degrees. Therefore, a wider overall projection can be achieved. Although the optical expander causes distortion in the overall projection, this distortion can be compensated for by designing the individual images appropriately. Therefore, the use of an optical expander is particularly suitable for MLA applications using a variety of beam paths. Advantageously, optical expanders can be manufactured very economically. When using plastic as the material, optical expanders can be produced using conventional molding techniques.

[0029] In some embodiments of the optical device, the optical expander is arranged such that the input surface is parallel to the imaging plane and receives the beam path from the MLA.

[0030] The input surface and the MLA can be aligned relative to each other such that all beam paths are received by the input surface. Therefore, the lateral extent of the input surface can be equal to or greater than the lateral extent of the MLA. The MLA and the input surface can be spaced apart. Advantageously, an optical expander can be mounted in front of the MLA such that all beam paths are received and redirected by the optical expander.

[0031] In some embodiments, the optical expander is arranged such that a first output surface of the optical expander is provided to guide a first subset of the beam channel to a first sub-region of the projection plane, and a second output surface of the optical expander is provided to guide a second subset of the beam channel to a second sub-region of the projection plane.

[0032] The beam path received by the input surface propagates through the optical expander and exits at the output surface of the optical expander. The beam path is released at the output surface, allowing it to propagate further toward the projection plane. This can mean that the first and second output surfaces deflect a first subset and a second subset of the beam path, respectively, in different directions. Deflection can occur, for example, through reflection, refraction, or diffraction. However, beam path deflection can also occur at the input surface or within the optical expander.

[0033] The first and second sub-regions of the projection plane can be different from each other. This means that the first and second sub-regions can be spatially separated from each other in the projection plane. However, the first and second sub-regions can also overlap at least partially. Starting from the optical expander, the first sub-region can be in a different direction than the second sub-region. Advantageously, the first and second output surfaces can be arranged such that different subsets of the beam path can be guided in different directions.

[0034] In some embodiments, the optical extender includes at least one additional output surface provided to direct a further subset of the beam path to a further sub-region of the projection plane.

[0035] Depending on the number of output surfaces, there may be more than one additional subset of beam channels and more than one additional sub-region of projection plane. In some embodiments, different output surfaces are provided to direct different subsets of beam channels to the same sub-region of projection plane.

[0036] As described above, this could mean that at least one additional output surface deflects another subset of the beam path in another direction. Deflection can occur, for example, through reflection, refraction, or diffraction. However, deflection of another subset of the beam path may have already occurred at the input surface or within the optical expander.

[0037] Other sub-regions of the projection plane can differ from the first and second sub-regions. This means that these other sub-regions can be spatially separated from the other sub-regions. However, these other sub-regions can also at least partially overlap with the other sub-regions. Starting from the optical expander, these other sub-regions can be in different directions from the other sub-regions. Advantageously, the first and second output surfaces can be arranged such that different subsets of the beam path can be guided in different directions.

[0038] In some embodiments, at least one of the output surfaces of the optical extender is provided as a corresponding subset of the beam channel to be guided by beam refraction at the respective output surface.

[0039] Beam refraction occurs according to Snell's law. Snell's law states that the ratio of the sines of the angle of incidence and the angle of refraction is equal to the ratio of the phase velocities in the two media of interest, or the reciprocal of the ratio of the refractive indices of the two media. In this case, the first medium is the material used for the optical expander, such as glass. The second medium is the environment, such as air. The angles of incidence and refraction depend on the inclination of the corresponding output surfaces. Advantageously, beam refraction can be used to efficiently guide a subset of the beam path in a specific direction.

[0040] In some embodiments, the optical expander includes an additional surface that enables total internal reflection of the light beam within a portion of the optical expander, such that at least one subset of the beam path is deflected within a portion of the optical expander.

[0041] Total internal reflection (TIR) ​​typically occurs when a wave in one medium reaches the boundary with another medium at a sufficiently large angle of incidence, provided that the second (“outer”) medium is transparent to the wave and allows it to travel faster than in the first (“inner”) medium. This means that TIR occurs at the interface of two non-absorbent media with different propagation speeds if the angle of incidence exceeds a certain value known as the critical angle for total reflection. The wave then no longer enters the second medium but is almost completely reflected back into the first medium.

[0042] In this case, the wave is an electromagnetic wave in the visible wavelength range, i.e., light. The critical angle is determined as θ using Snell's law. c =arcsin(n2 / n1), where n2 is the refractive index of the second medium (e.g., air), and n1 is the refractive index of the first medium (e.g., the material of the optical expander, glass). For TIR to occur, the refractive index of the first medium (the material of the optical expander) can be greater than the refractive index of the second medium (e.g., air). Furthermore, the tilt of another surface of the optical expander relative to the propagation of the beam path can cause the angle of incidence to exceed the critical angle.

[0043] An optical expander can have more than one additional surface in which the transflection (TIR) ​​of the beam can be realized. This means that the beam can be deflected multiple times within the optical expander via TIR. This further means that the beam path is guided within the optical expander to the corresponding output surface of the expander. By TIR, the beam path is deflected, thereby changing the direction of beam propagation. Advantageously, the guidance of a subset of the beam path toward a specific direction can be performed efficiently by means of TIR. In this way, the direction of the corresponding subset of the beam path can diverge even more than if the beam were refracted at the output surface.

[0044] In some embodiments, at least one of the output surfaces of the optical extender is tilted relative to the input surface of the optical extender.

[0045] This means that the normal vector of at least one output surface is not parallel to the normal vector of the input surface. However, there may be at least one output surface that is parallel to the input surface of the optical expander. Advantageously, by tilting at least one output surface relative to the input surface of the optical expander, the direction in which a subset of the beam path is guided can be controlled.

[0046] In some embodiments, at least two of the output surfaces of the optical extender are tilted relative to each other.

[0047] This means that the normal vector of at least one output surface is not parallel to the normal vector of the other output surface. However, there may be at least one output surface that is parallel to the other output surface of the optical expander. Advantageously, by tilting at least two output surfaces relative to each other, the direction to which a subset of the beam path is guided can be independently controlled.

[0048] In some embodiments, an optical extender is provided to extend the illumination area FOI such that the overall projection on the projection plane is greater than the individual projection on one of the sub-regions of the projection plane.

[0049] As described above, the Field of Interest (FOI) is defined by the width of the light cone emanating from the projection optics and extending toward the projection plane. The wider the light cone, the larger the overall projection on the projection plane can be. The optical expander expands the FOI by fanning out a beam path: a first subset of the beam path is directed to a first sub-region of the projection plane, while a second subset of the beam path is directed to a second sub-region of the beam path. Note that the first and second sub-regions can be in different directions. Therefore, the overall projection is greater than each of the individual projections. In other words, individual projections may only cover their respective sub-regions of the projection plane, while the overall projection covers the sum of the sub-regions.

[0050] As mentioned above, the aperture angle (FOI) is limited in conventional devices without optical expanders. In such systems, the light cone has a half-cone angle of approximately 10.5 degrees. By fanning out the beam path using an optical expander, the aperture angle can be increased to, for example, 30 degrees.

[0051] In some embodiments, the imaging system includes a patterned mask arranged in an imaging plane, the patterned mask providing individual images distributed on the imaging plane.

[0052] The pattern mask can be self-emissive, transmissive, or reflective. In the case of a self-emissive pattern mask, it can include an array of light sources, such as LEDs. By activating a first set of light sources, a first pattern is generated, which forms the first volumetric image among multiple images. Similarly, by activating a second set of light sources arranged at a distance from the first set of light sources, a second pattern is generated, forming the second volumetric image. The pattern mask can include multiple sets of light sources. The distribution of the light source groups on the pattern mask corresponds to the distribution of individual images on the imaging plane.

[0053] If the pattern mask is reflective, it may include a reflective structure. The reflective structure is illuminated from the front side of the pattern mask by at least one light source, causing the light to be reflected by the reflective structure. The front side of the pattern mask faces the MLA. The portion reflecting the light forms multiple images.

[0054] When the pattern mask is transmissive, it exhibits a variation in its transmittance in the lateral direction. The pattern mask can be illuminated by at least one light source, and the imaging system may include at least one light source. The light source can illuminate the pattern mask from the rear side, meaning the pattern mask is positioned between the light source and the MLA. Multiple images are generated in the imaging plane through portions of the light transmitted by the pattern mask. Individual images can be binary-coded, grayscale-coded, or even color-coded. The transmissive portion of the pattern mask can transmit the entire spectrum. However, various transmissive portions of the pattern mask can also transmit light within specific wavelength ranges, such as the red, green, or blue wavelength ranges. It is also possible to vary the transmittance of the corresponding transmissive portion of the pattern mask for specific wavelength ranges.

[0055] The pattern mask may include a chromium layer, which is structured through a photolithography process. When the pattern mask is illuminated from the back, light is blocked by the chromium layer and transmitted through the portions of the pattern mask where the chromium layer has been removed. Thus, multiple patterns are generated by the transmitted light, each forming an individual image. The patterns or individual images are spatially separated from each other, such that they are distributed on the imaging plane. Individual images can be generated in an analog, continuous, or pixelated manner.

[0056] Multiple images / patterns can be efficiently generated using pattern masks, especially transmission pattern masks. Pattern masks can be tailored to the requirements of specific applications. For example, if a specific overall projection is needed, the features of individual images on the pattern mask can be calculated by tracing back to the pattern mask side.

[0057] In some embodiments, the imaging system includes a light source provided to display multiple images.

[0058] In some other embodiments, multiple light sources are provided. As described above, the light sources or multiple light sources can be arranged on the pattern mask (in the case of a self-emissive, emission imaging system), in front of the pattern mask (in the case of a reflective imaging system), or behind the pattern mask (in the case of a transmissive imaging system). Advantageously, the light sources can emit light across the entire wavelength spectrum. However, light sources that emit monochromatic light are also possible. If multiple light sources are used, each light source can emit light within a specific wavelength range, such as emitting the full RGB spectrum.

[0059] In some embodiments, the imaging system further includes a collimating lens and / or a condenser lens or condenser lens array, wherein the collimating lens and condenser lens or condenser lens array are provided to form a beam path of the light source.

[0060] A collimating lens can be positioned between the light source and the imaging plane. Advantageously, a collimating lens is used to generate light from a diverging light source with an approximately parallel beam path. This means that a collimating lens can direct light in a specific direction.

[0061] A condenser lens or array of condenser lenses can be positioned between the collimating lens and the imaging plane. Advantageously, the condenser lens or array of condenser lenses can bring as much light from the light source into the imaging beam path as possible and ensure that each individual image is uniformly illuminated.

[0062] In some embodiments, the microlens array further includes a substrate having a main extension plane parallel to the imaging plane and including a rear side facing the imaging plane and a top side facing the optical expander. The microlenses of the MLA are arranged on the top side of the substrate.

[0063] The substrate can include a transparent material, such as glass. The microlens of the MLA can be in direct contact with the substrate. If a patterned mask is used, it can be positioned on the back side of the substrate, with the front side of the patterned mask in direct contact with the back side of the substrate. The thickness of the substrate can be selected based on the focal length of the microlens. This means that the distance between the microlens and the imaging plane / patterned mask can approximately correspond to the focal length of the microlens.

[0064] If a condenser lens array is used, it can be placed on the back side of the pattern mask so that the condenser lens array is in direct contact with the back side of the pattern mask.

[0065] Advantageously, processing the substrate from both sides facilitates the production of optical devices. Therefore, the optical devices can be compact and the overall system size can be reduced.

[0066] In some embodiments, the projection plane is tilted relative to the imaging plane, or the projection plane is a freeform surface.

[0067] However, in other embodiments, the projection plane is parallel to the imaging plane. The projection plane can be a screen included in the optical device. It is also possible for the projection plane to be formed by a wall or ground that is not part of the optical device.

[0068] Advantageously, the optical equipment can be adapted to any desired projection plane. Multi-channel projection via the MLA allows for increased depth of focus in individual projections. Therefore, for individual projections, there are essentially no problems if the projection plane has a laterally variable distance to the MLA.

[0069] In addition, an optical device is provided, which includes an optical apparatus, wherein the optical apparatus is specifically an illuminator or a projector.

[0070] Specifically, the optics can be used in any illumination module and projection system that requires a wide field of view (FOI). Optics can be used in, for example, automotive applications such as welcome light carpets (WLCs), interior dome lights, or wide-field-of-view headlights. In the case of WLCs, it may be desirable for the WLC to project perpendicular to the door line. Therefore, the WLC requires a larger FOI to allow it to be positioned closer to the door. However, the optics can also be used in home applications, such as for ceiling light projection. The optics can also be used in mobile and smart devices, such as for keyboard projection.

[0071] This objective is also achieved through a method for forming a global projection. This method involves generating multiple images distributed across an imaging plane.

[0072] It also includes assigning microlenses of the microlens array MLA to corresponding individual images in multiple images, and forming corresponding beam channels by projecting the corresponding individual images toward the projection plane.

[0073] It also includes providing an optical expander and arranging the optical expander between the MLA and the projection plane. The optical expander includes an input surface facing the MLA and at least two output surfaces facing the projection plane. The optical expander fans out the beam path and guides it onto the projection plane.

[0074] The method also includes individual projections that form individual images on the projection plane through beam channels guided onto the projection plane, and at least partially superimposing the individual projections.

[0075] Advantageously, a global projection can be generated on inclined, curved, or free-form surfaces. Furthermore, the field of view (FOI) can be advantageously expanded by using an optical expander. Therefore, a wider global projection can be achieved.

[0076] Other embodiments of the method based on the above-described pixel arrangement will become apparent to those skilled in the art. Attached Figure Description

[0077] The following description of the accompanying drawings further illustrates and explains exemplary embodiments. Functionally identical or having the same effect components are denoted by the same reference numerals. Identical or substantially identical components may be described only with respect to the drawings in which they first appear. Their descriptions are not necessarily repeated in subsequent drawings.

[0078] Figure 1 A cross-section of an example optical device is shown.

[0079] Figure 2 It shows that according to Figure 1 The example is a top view of a pattern mask.

[0080] Figure 3 It shows that according to Figure 1 An example of the overall projection on an inclined surface.

[0081] Figure 4 A cross-section of an embodiment of the optical device is shown.

[0082] Figure 5 It shows that according to Figure 4 A top view of the pattern mask of an embodiment.

[0083] Figure 6 It shows that according to Figure 4 The embodiment is the overall projection on the inclined surface.

[0084] Figure 7 A cross-section of another embodiment of the optical device is shown.

[0085] Figure 8 It shows that according to Figure 7 A top view of the pattern mask of an embodiment.

[0086] Figure 9 It shows that according to Figure 7 The embodiment is the overall projection on the inclined surface.

[0087] Figure 10 A cross-section of another embodiment of the optical device is shown.

[0088] Figure 11 A cross-section of another embodiment of the optical device is shown.

[0089] Figures 12a-12c A schematic diagram of an exemplary projection plane according to an embodiment is shown. Detailed Implementation

[0090] Figure 1 A cross-section of an exemplary conventional optical device 1 is shown. According to... Figure 1 The optical device 1 includes an imaging system 2, which generates multiple images distributed on an imaging plane 3. Figure 1 Three individual images 4 are shown, indicated by small arrows; however, this number is merely illustrative.

[0091] As indicated, multiple images can be generated by means of a transmission pattern mask 5 arranged in the imaging plane 3. The pattern mask 5 is illuminated by a light source 40 (not shown), wherein a collimated beam 6 strikes the pattern mask 5 from the rear side 7.

[0092] The optical device 1 also includes multiple microlenses 8 of a microlens array (MLA) 9. Figure 1 Three microlenses 8 are shown, corresponding to the number of individual images 4. Typically, the number of individual images 4 can match the number of microlenses 8. The pattern mask 5, and therefore the imaging plane 3, is arranged between the light source 40 and the MLA 9.

[0093] Each microlens 8 is assigned to a corresponding individual image 4 from a plurality of images. Each microlens 8 has an optical axis 10, as shown by the dashed line, which may have an offset 11 relative to the individual image 4. The resulting de-centration of the microlens 8 relative to the assigned individual image 4 is related to the projection distance.

[0094] Each microlens 8 is arranged such that it forms a corresponding beam path 12 by projecting a corresponding individual image 4 onto the projection plane 13. Therefore, an individual projection 14 is formed on the projection plane 13. According to... Figure 1 In the example, each individual projection 14 is formed on the same portion of the projection plane 13. As indicated by the large arrow, a global projection 15 is formed on the projection plane 13 by superimposing all individual projections 14.

[0095] Each individual image 4 shows a version of the overall image or the overall projection 15, respectively. For example... Figure 1As shown, the projection plane 13 is tilted relative to the imaging plane 3. This means that the distance of the projection plane 13 from the MLA9 varies depending on the position of the projection plane 13 in the longitudinal direction z. The longitudinal direction z is transverse to the imaging plane 3 and parallel to the projection plane 13. In order to generate a distortion-free overall projection 15, it may be necessary for the individual images 4 to be slightly different from each other. Therefore, the individual images 4 may be pre-distorted relative to each other and / or relative to the overall projection 15. For example, pre-distortion corrects distortion caused by the divergence of the beam path 12 of the individual images 4 or the magnification of the individual images 4.

[0096] Figure 2 It shows that it can be based on Figure 1 A top view of an exemplary patterned mask 5 used in the optical device 1. The patterned mask 5 may include, for example, a structured chromium layer. The portions of the patterned mask 5 where the chromium layer has been removed are transparent, while the portions of the patterned mask 5 where the chromium layer remains are opaque.

[0097] Therefore, multiple patterns are generated by irradiating the pattern mask 5 from the rear side 7. Figure 2 In the example, the patterns are arranged on a regular hexagonal grid. Each pattern is spaced apart from its adjacent patterns, such that the patterns are distributed on the pattern mask 5. Each pattern forms an individual image 4 in the imaging plane 3.

[0098] Figure 3 It shows that according to Figure 2 The overall projection 15 of the pattern mask 5. The overall projection 15 is projected onto the projection plane, wherein the projection plane is inclined relative to the imaging plane 3 (see...). Figure 1 The overall projection 15 has a length l in the longitudinal direction z and a width w in the transverse direction x, where the transverse direction x may be parallel to the imaging plane 3. In this example, the overall projection 15 is formed by four rectangles, where the rectangles increase in the longitudinal direction. Note that each individual image 4, i.e., each pattern, shows a distorted version of the overall projection 15, as shown in... Figure 2 and Figure 3 As can be seen in the image, pre-distortion compensation is performed to compensate for distortion caused by projection onto the tilted projection plane 13. The overall projection 15 is generated by superimposing the individual projections 14 of the individual images 4.

[0099] Figure 3 The outline of the light cone 16 is also shown, which is formed by the beam channel 12 projected onto the projection plane 13 and generating the overall projection 15. Note that the width w of the overall pattern is limited to the width of the light cone 16, i.e., limited to the semi-cone angle of the light cone 16. Therefore, according to Figures 1 to 3 In conventional optical equipment 1, the maximum width w of the overall projection 15 to be displayed is limited.

[0100] Figure 4A cross-section of an embodiment of the optical device 1, including the optical extender 17, is shown. This means that according to... Figure 4 Optical equipment 1 and Figure 1 The example shown differs in that it also illustrates an optical expander 17 arranged between the MLA 9 and the projection plane 13. Corresponding to... Figure 1 The example of the element based on Figure 4 The components are indicated by the same reference numerals. Figure 4 Only two individual images (4) are shown; however, this number is merely exemplary. Correspondingly, Figure 4 Two microlenses 8 of MLA 9 are shown, which form corresponding beam channels 12 by projecting corresponding individual images 4 toward projection plane 13.

[0101] According to Figure 4 In this embodiment, the individual images 4 differ from each other not only in that they are distorted relative to each other. Figure 4 The upper individual image 4 shown represents a first subset 18 of individual image 4, illustrating a version of the first part 19 of the overall projection 15. This is indicated by the rhombus shown in the upper individual image 4. The lower individual image 4 represents a second subset 20 of individual images 4, illustrating a version of the second part 21 of the overall projection 15. This is indicated by the arrow in the lower individual image 4.

[0102] Figure 4 The optical expander 17 of the embodiment includes an input surface 22 facing the MLA 9 and two output surfaces 23, 26 facing the projection plane 13. The optical expander 17 is arranged such that the input surface 22 is parallel to the imaging plane 3 and receives the beam path 12 from the MLA 9.

[0103] Furthermore, the optical expander 17 is arranged such that the first output surface 23 of the two output surfaces 23, 26 guides the first subset 24 of the beam channel 12 to the first sub-region 25 of the projection plane 13. The first subset 24 of the beam channel 12 corresponds to the beam channel 12 formed by projecting the individual image 4 by means of the MLA 9.

[0104] The second output surface 26 of the two output surfaces 23, 26 guides the second subset 27 of the beam channel 12 to the second sub-region 28 of the projection plane 13, wherein the second subset 27 of the beam channel 12 corresponds to the beam channel 12 formed by projecting the individual image 4 by means of the MLA 9.

[0105] Starting from the optical expander 17, the first sub-region 25 and the second sub-region 28 of the projection plane 13 are in different directions. Therefore, the optical expander 17 fans out the beam path 12. Fanning out and guiding the beam path 12 can occur through beam refraction at the output surfaces 23, 26. However, beam refraction may have already occurred at the input surface 22 of the optical expander 17, such as... Figure 4 As shown.

[0106] Individual projections 14 of individual image 4 are formed on the projection plane via beam channels 12 guided onto the projection plane. This means that a first subset 24 of beam channels 12 forms individual projections 14 on a first sub-region 25 of the projection plane 13, where these individual projections 14 are superimposed on a first portion 19 of the overall projection 15. A second subset 27 of beam channels 12 forms individual projections 14 on a second sub-region 28 of the projection plane 13, where these individual projections 14 are superimposed on a second portion 21 of the overall projection 15.

[0107] exist Figure 4 In this embodiment, the first sub-region 25 and the second sub-region 28 of the projection plane 13 are different but overlap. This means that in the overlapping region 29, the first subset 24 and the second subset 27 of the beam channel 12 also overlap each other.

[0108] Figure 5 It shows that it can be based on Figure 4 A top view of an exemplary transmission pattern mask 5 used in optical device 1. Figure 5 In the example, the patterns are arranged in two separate portions 30 of the pattern mask 5. Each portion 30 forms a regular pattern grid. Each pattern within a corresponding portion 30 is spaced apart from its adjacent pattern, such that all patterns are distributed on the pattern mask 5. Each pattern forms an individual image 4 in the imaging plane 3.

[0109] Figure 6 It shows that according to Figure 5 The corresponding overall projection 15 of the pattern mask 5. The overall projection 15 is projected onto the projection plane, wherein the projection plane is inclined relative to the imaging plane 3 (see...). Figure 4 In this example, the overall projection 15 is formed by five rectangles. Figure 6 The outlines of two light cones 16 are also shown, which are formed by a first subset 24 and a second subset 27 of the beam channels 12 that are guided onto the projection plane 13 and generate the global projection 15. The two light cones 16 overlap so that they can be regarded as a single global light cone 16.

[0110] Figure 6 The length l of the overall projection 15 is equal to Figure 3The overall projection 15 has a length l. However, the overall projection 15 of this embodiment has a wider width w because the global light cone 16 has a larger cone angle. Therefore, according to Figures 4 to 6 The embodiments have more than according to Figures 1 to 3 The example shows a larger illumination area. This means that the FOI can be extended by the optical expander 17.

[0111] Figure 7 A cross-section of another embodiment of optical device 1 is shown. According to... Figure 7 The functional principle of the embodiment is similar to that according to Figure 4 The functional principle of the embodiment. Therefore, according to... Figure 4 The elements corresponding to the embodiments are based on Figure 7 The components are indicated by the same reference numerals.

[0112] Figure 7 Three individual images (4) are shown; however, this number is merely exemplary. Correspondingly, Figure 7 The three microlenses 8 of the MLA9 are shown, which form corresponding beam channels 12 by projecting the corresponding individual images 4 toward the projection plane 13.

[0113] As in Figure 4 As in the previous embodiment, the individual images 4 differ from one another, not only in that they are distorted relative to each other. Figure 7 The upper individual image 4 shown represents a first subset 18 of individual image 4, illustrating a version of the first part 19 of the overall projection 15. The lower individual image 4 represents a second subset 20 of individual image 4, illustrating a version of the second part 21 of the overall projection 15. The middle individual image 4 represents a third subset 31 of individual image 4, illustrating a version of the third part 32 of the overall projection 15.

[0114] Figure 7 The optical expander 17 of the embodiment includes an input surface 22 facing the MLA 9 and three output surfaces 23, 26, 33 facing the projection plane 13. The optical expander 17 is arranged such that the input surface 22 is parallel to the imaging plane 3 and receives the beam path 12 from the MLA 9.

[0115] Furthermore, the optical expander 17 is arranged such that the first output surface 23 of the three output surfaces 23, 26, 33 guides the first subset 24 of the beam channel 12 to the first sub-region 25 of the projection plane 13. The first subset 24 of the beam channel 12 corresponds to the beam channel 12 formed by projecting the individual image 4 by means of the MLA 9.

[0116] The second output surface 26 of the three output surfaces 23, 26, 33 guides the second subset 27 of the beam channel 12 to the second sub-region 28 of the projection plane 13, wherein the second subset 27 of the beam channel 12 corresponds to the beam channel 12 formed by projecting the individual image 4 by means of the MLA 9.

[0117] The third output surface 33 of the three output surfaces 23, 26, 33 guides the third subset 34 of the beam channel 12 to the third sub-region 35 of the projection plane 13, wherein the third subset 34 of the beam channel 12 corresponds to the beam channel 12 formed by projecting the individual image 4 by means of MLA 9.

[0118] Starting with the optical expander 17, the first sub-region 25, the second sub-region 28, and the third sub-region 35 of the projection plane 13 are in different directions. Therefore, the optical expander 17 fans out the beam path 12. Figure 7 In this embodiment, the fan-out and guiding of the beam path 12 occurs through total internal reflection within the optical expander 17. Therefore, the optical expander 17 includes an additional surface 36 that allows the beam to undergo total internal reflection within portions 37, 38 of the optical expander 17.

[0119] Figure 7 The optical expander 17 includes a first portion 37 in which a first subset 24 of the beam channel 12 is guided via a TIR to a first output surface 23. The first portion 37 includes two additional surfaces 36 such that the first subset 24 of the beam channel 12 is internally deflected twice before reaching the first output surface 23.

[0120] The optical expander 17 also includes a second portion 38, wherein a second subset 27 of the beam channel 12 is guided to the second output surface 26 via TIR. This second portion 38 also includes two additional surfaces 36, such that the second subset 27 of the beam channel 12 is internally deflected twice before reaching the second output surface 26. The number of portions 37, 38 where TIR occurs is arbitrary, such that the number of portions in this embodiment is merely an example.

[0121] The third subset 34 of beam channel 12 exits the optical expander 17 at the third output surface 33 in the central portion 39 of the optical expander 17. Figure 7 In the example, the subset is not deflected internally.

[0122] As if based on Figures 4 to 6 As in the previous embodiment, individual projections 14 of individual images 4 are formed on the projection plane via beam channels 12 guided onto the projection plane, wherein they are at least partially superimposed. Figure 7In this embodiment, the first sub-region 25, the second sub-region 28, and the third sub-region 35 of the projection plane 13 are different but overlap, forming two overlapping regions 29. There, different subsets of the beam channel 12 also overlap each other.

[0123] Figure 8 It shows what can be used according to Figure 7 A top view of an exemplary transmission pattern mask 5 of optical device 1. Figure 8 In the example, the patterns are arranged in three separate portions 30 of the pattern mask 5. Each portion 30 forms a regular pattern grid. Each pattern within a corresponding portion 30 is spaced apart from its adjacent pattern, such that all patterns are distributed on the pattern mask 5. Each pattern forms an individual image 4 in the imaging plane 3.

[0124] Figure 9 It shows that according to Figure 8 The corresponding overall projection 15 of the pattern mask 5. The overall projection 15 is projected onto the projection plane, wherein the projection plane is inclined relative to the imaging plane 3 (see...). Figure 7 In this example, the overall projection 15 is formed by six rectangles. Figure 9 The outlines of three light cones 16 are also shown, which are formed by a first subset 24, a second subset 27, and a third subset 34 of the beam channel 12 that is guided onto the projection plane 13 and generates the global projection 15. The three light cones 16 overlap so that they can be regarded as a single global light cone 16.

[0125] Figure 9 The length l of the overall projection 15 is equal to Figures 3 to 6 The length l of the overall projection 15. However, the width w of the overall projection 15 in this embodiment is even greater than... Figure 6 The aperture is wider because the global light cone 16 has a larger aperture angle. Therefore, according to Figures 7 to 9 The embodiments have more than according to Figures 4 to 6 The embodiment provides a larger illumination area. This means that the FOI can be further extended by an optical extender 17 capable of achieving TIR.

[0126] Figure 10 A cross-section of another embodiment of the optical device 1 is shown. The optical device 1 includes an imaging system 2, which includes a light source 40 mounted on a carrier 41. The imaging system 2 also includes a collimating lens 42 disposed in front of the light source 40, such that the collimating lens 42 can generate an approximately parallel beam path of light from the light source 40. The collimating lens 42 is disposed between the light source 40 and a condenser lens array 43.

[0127] A condenser lens is provided to ensure that each individual image 4 is uniformly illuminated. Therefore, a condenser lens array 43 is attached to the rear side 7 of the pattern mask 5. The condenser lens array 43 can be attached to the pattern mask 5 such that each condenser lens covers the corresponding individual image 4.

[0128] according to Figure 10 The optical device 1 also includes a transparent substrate 44 having main extending planes parallel to the imaging plane 3 and the pattern mask 5, respectively. The substrate 44 includes a top side 45 on which an MLA 9 is disposed. The MLA 9 is in direct contact with the substrate 44. A pattern mask 5 having a condenser lens array 43 is disposed on the rear side 46 of the substrate 44. The front side 47 of the pattern mask 5 is in direct contact with the rear side 46 of the substrate 44. This means that the illustrated embodiment of the optical device 1 has a compact design, wherein a portion of the imaging system 2 (i.e., the condenser lens array 43 and the pattern mask 5) is attached to the substrate 44 including the MLA 9.

[0129] according to Figure 10 Optical device 1 also includes similar Figure 4 The optical expander 17 is shown. Two exemplary beams 6 are shown to illustrate beam refraction at one of the output surfaces 23, 26 of the optical expander 17.

[0130] Figure 11 A cross-section of another embodiment of optical device 1 is shown. This embodiment is similar to that according to... Figure 10 The difference in the embodiments is that it includes the same as Figure 7 The optical expander 17 shown is similar to the optical expander 17 shown. Several beams 6 are depicted to show total internal reflection of the beams within a portion of the optical expander 17. In the central portion 39 of the optical expander 17, the beams exit the optical expander 17 without being reflected.

[0131] Figures 12a to 12c Each showed including according to Figures 4 to 11 The optical device 1 includes an optical element 48. The optical element 48 may be, for example, a projector or an irradiator. The optical element 48 may include a housing in which the optical device 1 is integrated.

[0132] exist Figure 12a The diagram shows an optical device 48 that illuminates and / or projects onto a parallel (i.e., non-tilted) projection plane 13 (e.g., a screen). This means that the normal vector of the projection plane 13 is parallel to the optical axis 49 of the light cone 16 emitted by the optical device 48. The projection plane 13 is spaced apart from the optical device 48 by a distance d.

[0133] exist Figure 12bThe diagram illustrates an optical device 48 that illuminates and / or projects onto an inclined projection plane 13 (e.g., a screen or ground). This means that the normal vector of the projection plane 13 is transverse to the optical axis 49 of the light cone 16 emitted by the optical device 48. The angle δ between the normal vector of the projection plane 13 and the optical axis 49 of the light cone 16 depends on the application. For example, if the optical device 48 is used for a welcome light carpet in an automotive application, the angle δ is typically between 65 and 85 degrees. In the vertical direction y, perpendicular to the projection plane 13, the optical device 48 may be spaced from the projection plane 13 by a height h. For example, if the optical device 48 is used for a welcome light carpet in an automotive application, the height h is typically between 150 mm and 270 mm.

[0134] exist Figure 12c The image shows an optical device 48 that illuminates and / or projects onto a projection plane 13, which forms a freeform surface. This means that the projection plane 13 is non-planar.

[0135] To familiarize the reader with the novel aspects of the concept, embodiments of the optical device 1 disclosed herein have been discussed. Although preferred embodiments have been shown and described, those skilled in the art can make many changes, modifications, equivalents, and substitutions to the disclosed concept without unnecessarily departing from the scope of the claims.

[0136] It should be understood that this disclosure is not limited to the disclosed embodiments and the content specifically shown and described above. Rather, features recited in separate dependent claims or the specification may be advantageously combined. Furthermore, the scope of this disclosure includes variations and modifications that will be apparent to those skilled in the art and fall within the scope of the appended claims.

[0137] The term "comprising" as used in the claims or description does not exclude other elements or steps of the corresponding feature or process. When the terms "a" or "an" are used in conjunction with a feature, they do not exclude a plurality of such features. Furthermore, any reference numerals in the claims should not be construed as limiting the scope.

[0138] This patent application claims priority to German patent application 102020127181.6, the disclosure of which is incorporated herein by reference.

[0139] List of reference numerals

[0140] 1. Optical equipment

[0141] 2 Imaging System

[0142] 3 Imaging plane

[0143] 4 individual images

[0144] 5. Pattern Mask

[0145] 6 beams

[0146] 7. Back side of the pattern mask

[0147] 8 Microlenses

[0148] 9 Microlens Array

[0149] The optical axis of the 10 microlenses

[0150] 11 offset

[0151] 12 beam channels

[0152] 13 Projection Planes

[0153] 14 individual projections

[0154] 15 Overall Forecast

[0155] 16 light cones

[0156] 17 Optical Expander

[0157] The first subset of 18 individual images

[0158] 19. The first part of the overall projection

[0159] The second subset of 20 individual images

[0160] Part 2 of the overall projection

[0161] 22 Input Surface

[0162] 23 First Output Surface

[0163] The first subset of 24 beam channels

[0164] 25 Projection Plane First Sub-region

[0165] 26 Second Output Surface

[0166] The second subset of 27 beam channels

[0167] The second sub-region of the 28 projection plane

[0168] 29 overlapping regions

[0169] 30 pattern mask portion

[0170] The third subset of 31 individual images

[0171] 32. The third part of the overall projection

[0172] 33 Third Output Surface

[0173] The third subset of 34 beam channels

[0174] 35 Projection Plane Third Sub-region

[0175] 36 Other surfaces

[0176] The first part of the 37 optical expander

[0177] Part 2 of the 38 optical expander

[0178] 39. Central part of the optical expander

[0179] 40 light source

[0180] 41 carriers

[0181] 42 collimating lens

[0182] 43 Condensing Lens Array

[0183] 44 substrate

[0184] Top side of 45 substrate

[0185] 46 substrate rear side

[0186] 47. Front side of the pattern mask

[0187] 48 Optical Devices

[0188] The optical axis of the 49 light cone

[0189] d Distance

[0190] h height

[0191] l length

[0192] w width

[0193] x Horizontal direction

[0194] y (vertical direction)

[0195] z Longitudinal direction

[0196] δ Angle.

Claims

1. An optical device (1), comprising: -Imaging system (2), which is provided to generate multiple images (4) distributed on imaging plane (3). - A microlens array MLA (9), wherein the microlenses (8) of the MLA (9) are assigned to corresponding individual images (4) in the plurality of images and are provided to form corresponding beam channels (12) by projecting the corresponding individual images (4) toward a projection plane (13). - An optical expander (17) is disposed between the MLA (9) and the projection plane (13), the optical expander (17) including an input surface (22) facing the MLA (9) and at least two output surfaces (23, 26, 33) facing the projection plane (13), the optical expander (17) being provided to fan out and guide the beam path (12) onto the projection plane (13), such that -The individual projection (14) of the individual image (4) is formed on the projection plane (13) by the beam channel (12) guided to the projection plane (13), and - A global projection (15) is formed on the projection plane (13) by at least partially superimposing the individual projections (14). The optical expander (17) is arranged such that - The first output surface (23) of the optical expander (17) is provided to guide a first subset (24) of the beam channel (12) to a first sub-region (25) of the projection plane (13), and - The second output surface (26) of the optical expander (17) is provided to guide a second subset (27) of the beam channel (12) to a second sub-region (28) of the projection plane (13).

2. The optical device (1) according to claim 1, wherein the optical expander (17) is arranged such that the input surface (22) is parallel to the imaging plane (3) and receives the beam channel (12) from the MLA (9).

3. The optical device (1) according to claim 1 or 2, wherein the optical extender (17) includes at least one additional output surface (33) provided to guide an additional subset (34) of the beam channel (12) to an additional sub-region (35) of the projection plane (13).

4. The optical device (1) according to claim 1 or 2, wherein at least one of the output surfaces (23, 26, 33) of the optical expander (17) is provided to guide a corresponding subset (24, 27, 34) of the beam channel (12) by beam refraction at the respective output surfaces (23, 26, 33).

5. The optical device (1) according to claim 1, wherein the optical expander (17) includes an additional surface (36) that enables total internal reflection of the light beam within a portion (37, 38) of the optical expander (17), such that at least one of the subsets (24, 27, 34) of the beam channel (12) is deflected within the portion (37, 38) of the optical expander (17).

6. The optical device (1) according to claim 1 or 2, wherein at least one of the output surfaces (23, 26, 33) of the optical expander (17) is inclined relative to the input surface (22) of the optical expander (17).

7. The optical device (1) according to claim 1 or 2, wherein at least two of the output surfaces (23, 26, 33) of the optical expander (17) are inclined relative to each other.

8. The optical device (1) according to claim 1, wherein the optical extender (17) is provided for extending the illumination area such that the overall projection (15) on the projection plane (13) is greater than the individual projection (14) on one of the sub-regions (25, 28, 35) of the projection plane (13).

9. The optical device (1) according to claim 1 or 2, wherein the imaging system (2) includes a pattern mask (5) arranged in the imaging plane (3), the pattern mask (5) providing individual images (4) distributed on the imaging plane (3).

10. The optical device (1) according to claim 1 or 2, wherein the imaging system (2) comprises: - A light source (40) is provided to display the plurality of images (4). - Collimating lens (42), and / or - Condensing lens or condensing lens array (43). The collimating lens (42) and the condenser lens or condenser lens array (43) are provided to form the beam path of the light source (40).

11. The optical device (1) according to claim 1 or 2, wherein the MLA (9) further comprises a substrate (44) having a main extension plane parallel to the imaging plane (3) and including a rear side (46) facing the imaging plane (3) and a top side (45) facing the optical expander (17), wherein the microlens (8) of the MLA (9) is disposed on the top side (45) of the substrate (44).

12. The optical device (1) according to claim 1 or 2, wherein the projection plane (13) is inclined relative to the imaging plane (3), or wherein the projection plane (13) is a freeform surface.

13. An optical device (48) comprising an optical device (1) according to any one of claims 1-12, wherein the optical device (48) is an illuminator or a projector.

14. A method for forming an overall projection (15), the method comprising: - Generate multiple images distributed on the imaging plane (3), - The microlenses (8) of the microlens array MLA (9) are assigned to the corresponding individual images (4) in the plurality of images, and the corresponding individual images (4) are projected toward the projection plane (13) to form the corresponding beam channels (12). - Provide an optical expander (17) and arrange the optical expander (17) between the MLA (9) and the projection plane (13), the optical expander (17) including an input surface (22) facing the MLA (9) and at least two output surfaces (23, 26, 33) facing the projection plane (13), the optical expander (17) fans out the beam channel (12) and guides it onto the projection plane (13), -The individual projection (14) of the individual image (4) is formed on the projection plane (13) by the beam channel (12) guided to the projection plane (13), and - At least partially superimposed the individual projections (14). The optical expander (17) is arranged such that - The first output surface (23) of the optical expander (17) is provided to guide a first subset (24) of the beam channel (12) to a first sub-region (25) of the projection plane (13), and - The second output surface (26) of the optical expander (17) is provided to guide a second subset (27) of the beam channel (12) to a second sub-region (28) of the projection plane (13).

Images