Optical beamformer, projection device and method for constructing a condenser lens

Abstract

An optical beam former for generating an emerging light beam from an incident light beam comprises a condenser lens array comprising a plurality of condenser lenses, the plurality of condenser lenses configured for receiving the incident light beam; and a projection lens array comprising a plurality of projection lenses configured for receiving light from the condenser lens array and for radiating the emerging light beam. A footprint of at least a first condenser lens of the condenser lens array comprises a non-rectangular shape; and wherein at an adjoining region between the first condenser lens and an adjoining second condenser lens a height profile of the first condenser lens is adapted to the second condenser lens.

Description

[0001] Optical Beamformer, Projection Device and Method for Constructing a Condenser Lens

[0002] Description

[0003] The present invention relates to an optical beamformer for generating an emerging light beam from an incident light beam, to a projection device comprising such an optical beamformer and to a method for determining a shape of a plurality of condenser lenses that may, for example, serve for an optical beamformer described herein. The present invention particularly relates to pattern generation based on maskless double-sided micro-lens arrays, MLA, with freeform arbitrary-shaped lenslets and reduced straylight and highly efficient turn indicating projector.

[0004] Multi-channel pattern projection approach based on the masked fly’s eye condenser (FEC) [1] enables very compact projection systems with homogeneous and sharp output pattern with top-hat profile. In such projector the entrance lenslets act as condenser lenslets, which realize Kohler illumination, i.e. , they image the light source into the pupil of the addressed projector lenslet. Kohler illumination with completely filled pupil is a requirement for etendue conserving projection [2], This enables the smallest lateral extent of the projection system for the given target pattern. However, the use of absorbing slide mask array dramatically limits the transmission of the system, therefore reducing the resulting brightness of the projected pattern. Additionally, the presence of the absorbing mask layer enlarges the amount of steps in the replication process, and thus increases manufacturing cost.

[0005] FEC with entrance lenslets 1002 having footprint of the target pattern (Fig. 14a) enables efficient pattern projection without utilization of absorbing mask apertures, which remarkably enhances transmission and thus brightness, provided, that the entrance array still has 100 % fill-factor [3], However, shaping the entrance lenslets 1002 of a simple spherical or aspherical profile in an arbitrary manner creates localized straylight features 1004 caused by edges 1008 of the lenslets 1002 occurring around the projected pattern 1006. An example of a projected pattern with chevron-like lenslets is given in Fig. 14b.

[0006] In other words, Figs. 14a and 14b show simple chevron-shaped entrance lenslets with spherical profile and a corresponding pattern with localized straylight features.To suppress straylight in maskless MLA projection systems, some residual absorbing masks 1012 can be positioned at a short distance (« f, where f- the focal length of the lenslets) before or behind the entrance array [4], This would block-out only the regions between the lenslets 1002 (Fig. 15a). This will keep the brightness of the projected pattern constant but reduce straylight remarkably at the expense of slightly reduced size of projected pattern (Fig. 15b). Unfortunately, the use of absorbing mask array increases required steps for the polymer-on-glass replication (current state of the art) as well as excludes the use of the injection molding technology for mass production.

[0007] In other words, Fig. 15a and Fig. 15b show simply chevron-shaped entrance lenslets 1002 with residual masks 1012 and corresponding pattern 1006.

[0008] Another approach of reducing straylight in such systems is a decomposition of entrance lenslets’ shape into elementary features 1002a and 1002b, which can be tiled with 100 % fill-factor (Fig. 16a). Their images can be steered by exit lenslets in such a way, that they form a desired pattern [5], This, however, doesn’t guarantee to avoid disturbing effects and can lead to appearance of stray light on the exit MLA. Additionally, this approach might require an effort on suppressing visible seams 1014 or brightness steps between the elementary parts of the projected patterns (Fig. 16b and Fig. 16c).

[0009] In other words, Fig. 16a shows an arrangement of decomposed entrance lenslets and Figs.

[0010] 16b and 16c show corresponding patterns.

[0011] There is, thus, a need to improve projection of patterns.

[0012] An object of the present invention is, thus, to provide for an optical beamformer, a projection device and a method for determining the shape of condenser lenses that allow a high quality of the projected pattern whilst avoiding the disadvantages known from the art.

[0013] This object is achieved by the subject-matter as defined in the independent claims.

[0014] A finding of the present invention is that by avoiding height jumps or sag height jumps between the entrance lenslets, the generation of the disadvantageous straylight may be low or even avoided such that the complex arrangement of a light suppressing mask may be superfluous although not prevented. That is, as an alternative or in addition to knownconcepts, this generation of straylight may be avoided thereby rendering conventional counter measures to suppress the straylight unnecessary.

[0015] The inventors have found that a source of the straylight is a sag height jump between condenser lenses so that by avoiding said jumps at least in parts by adopting the sag profile, the height profile, respectively, a high quality of the projection maybe obtained.

[0016] The inventors have found that one of the main issues of straylight effects that lead to a reduction in projection quality are caused by sag height jumps, i.e., optical edges through which incident light is directed in an undesired way.

[0017] A solution presented according to the embodiments is to adapt the sag height profile, in particular, for non-rectangular shapes of condenser lenses to arrive at adapted height profiles which allows to maintain or even avoid such straylight and to have a good imaging or projection quality even without arranging an absorbing mask as being implemented in the prior art, although arranging such a mask is not prevented when implementing the present invention.

[0018] According to an embodiment, an optical beamformer for generating an emerging light beam from an incident light beam comprises a condenser lens array comprising a plurality of condenser lenses, the plurality of condenser lenses configured for receiving the incident light beam. A projection lens array of the optical beamformer comprises a plurality of projection lenses configured for receiving light from the condenser lens array and for radiating the emerging light beam. A footprint of at least a first condenser lens of the condenser lens array comprises a non-rectangular shape and, at an adjoining region between the first condenser lens and an adjoining second condenser lens, a height profile of the first condenser lens is adapted to the second condenser lens.

[0019] According to an embodiment, a projection device comprises such an optical beamformer and a light source configured for providing the incident light beam. The projection device may be, amongst others, a headlight, e.g., a headlight beam of a vehicle or for a vehicle but may also be a device usable for projecting a pattern, e.g., in a handheld device or a device installed in a mobile or immobile system.

[0020] Further embodiments relate to a method for determining a shape or layout of condenser lenses or entrance lenses based on adapting their height profile. Such a method comprises:Determining a shape of a pattern to be projected by use of the plurality of condenser lenses; and determining a height profile of the plurality of condenser lenses such that the height profiles of each condenser lens are adapted to a respective adjoining condenser lens(es).

[0021] Preferred embodiments of the present invention are now described whilst making reference to the accompanying drawings, in which:

[0022] Fig. 1a shows a schematic sideview of an optical beamformer according to an embodiment;

[0023] Fig. 1 b shows an enlarged view of a part of the condenser lens array of Fig. 1 a;

[0024] Fig. 2 shows a schematic enlarged sideview of a transition between condenser lenses according to an embodiment that may correspond to Fig. 1b;

[0025] Fig. 3a shows a schematic top view on the footprint of condenser lens according to an embodiment;

[0026] Fig. 3b shows a schematic view to show an image of a light source obtained by a square LED and built by a simple condenser lensletwith spherical or aspherical profile according to an embodiment;

[0027] Fig. 4a shows a schematic top view on a chevron-shaped footprint of a condenser lens according to an embodiment.

[0028] Fig. 4b shows a schematic representation of an array of condenser lenses according to Fig. 4a and an associated projection lens array;

[0029] Figs. 5a-b show a chevron-like entrance lenslet built of two mirrored cylindrical parallelogram-shaped lenslets according to an embodiment and a schematic representation of the image of the source;

[0030] Fig. 6a-d show schematic illustrations relating to effects of vertex-position variations in condenser lenses that use two mirrored anamorphic parallelogram-shaped lenslets according to an embodiment;Fig. 7a shows a schematic diagram of a distance between lenses being not optimized;

[0031] Fig. 7b shows an illustration related to Fig. 7a with distance being optimized according to an embodiment;

[0032] Fig. 8a-b show a sag distribution map and a 3D appearance of the sag jumpless array built from freeform chevron-shaped entrance lenslets according to an embodiment;

[0033] Fig. 9 shows a schematic diagram of a projection obtained with condenser lenses according to an embodiment;

[0034] Fig. 10a-b show schematic illustrations of a design example for a condenser lens according to an embodiment having more complex aperture shape with 8 corners;

[0035] Fig. 11a shows a schematic perspective view of an exit lenslets array according to an embodiment;

[0036] Fig. 11b shows an illustration of a resulting pattern projected at infinity with a single precollimated light source applied to the array of Fig. 11a;

[0037] Fig. 12 shows a schematic top view of an arrangement of two adjoining condenser lenses according to an embodiment comprising a continuous or steadily formed adjoining region;

[0038] Fig. 13 shows a schematic flow chart of a method according to an embodiment;

[0039] Fig. 14a-b show schematic views of a known fly’s eye condenser, FEC, with entrance lenslets having footprint of the target pattern and an example for chevron-like lenslets;

[0040] Fig. 15a-b show simply chevron-shaped entrance lenslets with residual masks and a corresponding pattern;

[0041] Fig. 16a shows an arrangement of decomposed entrance lenslets; andFig. 16b-c show patterns corresponding to Fig. 16a.

[0042] Equal or equivalent elements or elements with equal or equivalent functionality are denoted in the following description by equal or equivalent reference numerals even if occurring in different figures.

[0043] In the following description, a plurality of details is set forth to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other instances, well known structures and devices are shown in block diagram form rather than in detail in order to avoid obscuring embodiments of the present invention. In addition, features of the different embodiments described hereinafter may be combined with each other, unless specifically noted otherwise.

[0044] Embodiments described herein relate to arrays of lenses, in particular microlenses also referred to as lenslets. Arrays of microlenses that may implement a condenser lens array or a projection lens array may be referred to as micro lens array, MLA. The advantageous modifications presented by way of embodiments relate to a structure of the condenser lenses, and / or adaptation of their height profile at adjoining regions respectively. According to an embodiment, such a structure is part of an optical beamformer, whilst by including to such a beamformer a light source, a projection device may be obtained that also falls under the scope of the embodiments described herein.

[0045] Fig. 1a shows a schematic sideview of an optical beamformer 10 according to an embodiment. The optical beamformer 10 is implemented for generating an emerging light beam 12 from an incident light beam 14. For implementing this function, the optical beamformer comprises a condenser lens array having a plurality of condenser lenses 181 to 18n, the plurality of condenser lenses 18 configured for receiving the incident light beam 14. Condenser lens array 16 may comprise a substrate 22 carrying one or more of the plurality of condenser lenses 18. Alternatively or in addition, the condenser lenses 18 may be formed as a single, integral optical component thereby also implementing a functionality of a substrate.The optical beamformer 10 further comprises a projection lens array 24 comprising a plurality of projection lenses 26i to 26m, wherein the number m of projection lenses may be the same or different when compared to the number n of condenser lenses. The projection lenses 26i to 26mmay be formed on a side of the substrate 22 opposing the condenser lens array 16. The projection lenses 26 are configured for receiving light from the condenser lens array 16 and for radiating the emerging light beam 12. Optical components such as lenses, masks, substrates and the like may be arranged between arrays 16 and 24 but may be an optional feature and, thus, absent.

[0046] As shown in Fig. 1a, both arrays 16 and 24 may be placed on a common substrate. As an alternative, the arrays 16 and 24 may be placed on separated substrates, e.g., with an air gap between them.

[0047] An association between projection lenses 26 and condenser lenses 18 may be on a 1:1-association which may cause that at least one or even each condenser lens 18 is associated with exactly one projection lens 26. In another configuration, at least one condenser lens 18 may be associated with more than one projection lens 26. Such a configuration may be caused or may be based, e.g., by an inclination between arrays 16 and 26 causing that both arrays are not in parallel with one another. Also, based on an optical behavior of the condenser lenses 18 and / or based on characteristics of the incident collimated beam, it may be possible to illuminate more than one projection lens 26 with a single condenser lens 18. Such a configuration may be referred to as a 1:x configuration of condenser lenses (1) and projection lenes (x), with x > 1. Thereby, intentionally an effect may be caused to happen, that is usually tried to be avoided as cross-talk.

[0048] Those configurations are combinable, e.g., in different regions of array 16 and / or 24. According to an embodiment, a single condenser lens 18 may be configured for illuminating more than one projection lens 26.

[0049] Fig. 1b shows an enlarged view of a part of the condenser lens array 16 by illustrating, as a non-limiting example, two adjacent condenser lenses 18xand 18ythat abut each other or contact each other or are arranged adjacently to one another at an adjoining region 28. At the adjoining region 28, therein respectively, a height profile of condenser lens 18xis adapted to a height profile of condenser lens 18y. When compared to a possible but not necessarily planar transition 32, optical surfaces 34xand 34ymay still comprise some small but acceptable transitions as shown in Fig. 1b. A preferred embodiment of the presentinvention is that for the adapted height profile, the adjoining region 28 comprises a sag height jump of at most 30 % of a total sag profile height of the condenser lens 34x, a configuration that is described in more detail in connection with Fig. 2. In a preferred embodiment, the adapted height profile is an essentially jumpless height profile between adjacent lenses of the plurality of condenser lenses 18 in the condenser lens array 16.

[0050] When referring again to Fig. 1a and Fig. 1b, the condenser lens 18 comprising the adapted height profile comprises a non-rectangular shape of its footprint. A footprint may be considered as a base area covered by the lens, e.g., an area being covered on a substrate on which the lens molded or formed. In case of a substrate-less implementation, the aperture of the lens may be considered as the footprint.

[0051] The footprint is, by way of example, may be curved, e.g., circular or elliptical, i.e., curved beyond manufacturing tolerances. Alternatively or in addition, a polygonal shape may form at least a part of the footprint, wherein circular parts or curved parts and polygonal parts may be combined. In a preferred embodiment, the footprint is an irregular footprint. As an optional implementation, a footprint of the plurality of projection lenses 26 may follow the footprint of the plurality of condenser lenses of condenser lens array 16. That is, a geometry of the footprints may be similar to one another or may even be equal.

[0052] Fig. 2 shows a schematic enlarged sideview of a transition between condenser lenses 34xand 34ythat may correspond to Fig. 1b and may form a part of the condenser lens array 16 in the optical beamformer 10. Although in an ideal profile of the optical surfaces of the condenser lenses, the adjoining region 28 may comprise a lateral extension of almost zero, according to a real profile 38 that is obtained by manufacturing processes and the like, the lateral extension of adjoining region 28 is non-zero and indicated by parameter d in Fig. 2.

[0053] Within the adjoining region 28, although it might be preferred and in some embodiments even realized to have a sag height difference or sag heigh jump or being essentially zero, i.e., jumpless, the height difference 42 may comprise, in other embodiments, at most 30 % of a total sag height profile height of the condenser lens 34xand / or 34y, preferably at most 20 % or at most 15 %. Preferably, such an adaptation is performed between each pair of adjacently arranged condenser lenses such that each condenser lens of the plurality of condenser lenses comprises a footprint with a non-rectangular shape and comprises a height profile being adjusted with regards to an adjoining condenser lens in a respective adjoining region.In other words, according to an embodiment, an acceptable residual sag height jump 42 may be up to 30 %, up to 15 % or even up to 5 % from a total sag profile of the micro lens array, MLA. Alternatively or in addition, a shape of the sag jump may have a flank angle 0 being larger than 60°, preferably larger than 75° and even more preferably at least 89°. Alternatively or in addition, a radius of the tips, may comprise a rounding or an inner radius rthat is at most 15 pm, preferably at most 10 pm and more preferably at most 5 pm.

[0054] According to an embodiment a sag height jump flank 44 in the adjoining region 28 between condenser lenses 34xand 34y may be inclined by an angle 0 of at least 60°, preferably at least 70° and even more preferably at least 75° with regard to a surface of a substrate carrying the plurality of condenser lenses 16 so as to comply with the adapted height profile. The steeper flank 44 is, the less straylight may be expected.

[0055] The adjoining region 28 may comprise a lateral extension d along a direction from the first condenser lens 34xto the second condenser lens 34y(or vice versa) that is at most 15% from a total extension of the condenser lens along a direction from a center of one of the condenser lenses 34xto a center of the other condenser lens 34yto comply with the adapted height profile. Preferably, d is less than 15%, e.g., at most 12% or at most 10%. A further parameter of the condenser lens array 16 that may be implemented, possibly, at least influenced from the lateral extension d is a so-called fill-factor of the plurality of condenser lenses 16 in the condenser lens array being at least 85%, preferably more, e.g., at least 88% or at least 90% or even more.

[0056] As an alternative or in addition, whilst being however optional, a rounding r in Fig. 2 of a shape of the condenser lens 34xand / or 34yand in the adjoining region 28 comprises a radius of at most 15% from a total extension of the condenser lens along a direction from a center of the first condenser lens to a center of the second condenser lens to comply with the adapted height profile. For the example, as an alternative or at least a part of a straight or planar flank 44, a radius or curvature may be implemented that nevertheless leads to a dead zone d.

[0057] Alternatively or in addition, the dead zone d is at most 15pm, at most 10pm or at most 5pm. As a further consideration, a residual gap between micro lenses that may lead to a decreased fill-factor may be, at most, 15%, at most 10%, at most 5%, and most preferred at most 2% from the lateral extent between centers of micro lenses.Embodiments according to the presented solution underlying the invention may use arbitrary-shaped entrance lenslets with freeform profiles such that at least a subset of the plurality of condenser lenses comprises a footprint having a freeform profile. Such a subset may be arranged as a cluster, i.e., in a common area. According to an embodiment, each of the condenser lenses of the condenser lens array is adapted accordingly. Adapting the height profile may eliminate the sag height jumps, possibly completely, therefore dramatically reducing straight line effects and enabling a projection of a pattern with sharper and cleaner contours when compared to lenslets without adapted height profile. Although an effortful use of absorbing masks is still possible to further improve quality, such a use may be unnecessary in view of the improvements obtained by the adapted height profile. The costs of making entrance lenslets freeform might be a worsened imagining of the source in the exit lenslet plane and increased etendue, therefore, the solution may form a compromise between a straight light reduction and system etendue.

[0058] According to Figs. 3a and 3b, there is presented an implementation serving as a basis for some embodiments, where one, more, or each condenser lens represented by a condenser lens 18 of the condenser lens array comprises a footprint being chevron-shaped, thereby presenting an example of an irregular shaped footprint. In Fig. 3a there is shown a single lenslet 52 and an arrangement with regard to the exit lens 26 to avoid cross talk, i.e., keeping an image of the source within a corresponding projection lenslet 26. In absence of a further lenslet and in absence of an adjoining region to such additional lenslet, Fig. 3a does not yet illustrate an adapted height profile according to embodiments.

[0059] A chevron may be considered as comprising at least two or preferably exactly two anamorphic surfaces 46i and 462that are rotated within a parallelogram aperture. The anamorphic surfaces 46i and 462may each or both together comprise a toroidal or biconical shape. That is, the anamorphic surfaces 46i and / or 462may comprise a radius of curvature, ROC, comprises a value different from 0 for one or both relevant directions x, y. Further explanation will be given with reference to basic points T, II, P and Q, wherein once T and II may be mirrored in a plane defined by a plane comprising points Q and P to thereby define points T1 and U1.

[0060] Whilst Fig. 3a shows a schematic top view on the footprint of condenser lens 18, Fig. 3b shows a schematic view to show an image 47 of a light source, i.e., the source image,obtained by a square LED and further shows a rectangular shaped footprint of an exit microlens 26.

[0061] To allow a comparison with further embodiments described herein, Figs. 3a and 3b present an example with a simple chevron-like condenser lenslet 52 with spherical surface profiles, which generates sag height jumps between such lenslets in the array, see Fig. 3a. In this case, the best imagining of the light source into the pupil of the projection lenslet is achieved, which helps to utilize system etendue to its maximum or keep sufficient safety margin to avoid undesired cross-talk, see Fig. 3b. However, as described earlier, sag height jumps create pronounced localized straylight.

[0062] In other words, Fig. 3a shows a surface spherical chevron-like entrance lenslet and Fig. 3b shows a corresponding and schematic representation of the image of the source, e.g., a square LED capped within the extent of the exit lenslet 26, ensuring an absence of undesired cross-talk.

[0063] Fig. 4a shows a schematic top view on a footprint of a condenser lens 40 according to an embodiment.

[0064] By referencing Fig. 4a advantageous parameters for reforming the condenser lens 40 are described that allow a high degree of filling, e.g., approximately 100% whilst also avoiding jumps in joining regions to other lenses. For illustrating this, Fig. 4b shows a schematic view on a projection of a plurality of, e.g., six projection lenses 26i to 26e in connection with an example number of four condenser lenses 40i to 404. Additional condenser lenses, e.g., to obtain a 1:1 association between condenser lenses and projection lenses may be included in the condenser lens array.

[0065] In Fig. 4a, there is shown one of four similarly shaped condenser lenses in Fig. 4b, orientations of a radius of curvature ROCy, 48Y and orientations of a radius of curvature ROCx, 48x, i.e. , radially along orthogonal directions X and Y with regard to the anamorphic surface 46i and 462. As shown in Fig. 4b, at least a subset of the condenser lenses 26 that is possibly but not necessarily formed as a cluster, comprises a congruent footprint. At least for an arranged cluster the condenser lenses may comprise an adaptive height profile.

[0066] For the straylight suppression with the entrance lenslet shape, the shape corresponding to Fig. 14a, the sag height jumps may be reduced or even completely eliminated, i.e., at leastminimized. This may be implemented when the sag value at two overlapping points of the adjacent contour of the lenslet is equal or within a tolerance range. This may be difficult if the lenslet 40 has a simple spherical or aspherical curvature profile. To solve, embodiments propose that the condenser lens 40 is designed as freeform element with a single aperture, e.g., in a chevron-like contour, although other contours are not excluded. To achieve this, the condenser lens 40 may be designed as a combination of two mirrored anamorphic surfaces, rotated within an individual parallelogram-shaped aperture contour, the rotation being indicated by angle p in Fig. 4a.

[0067] In other words, Figs. 4a and 4b show chevron-like entrance lenslets, built of two mirrored anamorphic surfaces rotated within a parallelogram-shaped aperture.

[0068] In one simple example, each of these two lenslets may be implemented as a cylindrical lens with a finite ROCY and infinite ROXx, rotated by the same angle as the angle as the chevron, leading to angles and a being equal, i.e. , p = a. In this case, the sag may have the same value at all four points II, T, Q, and P and it may also be the same between the lines II - P and T - Q. This, however, may create a solution, where imaging of the pre-collimated light source by each of such cylindrical entrance lenslets onto the exit lenslet plane is affected, which may be an issue for the normal function of a fly’s eye condenser and may lead to undesired crosstalk as the image of the pre-collimated light source possibly exceeds the extent of the exit lenslet due to a lack of focusing along the rotated X direction as illustrated in Figs. 5a and 5b. In Fig. 5a, there is shown a schematic top view on a footprint of a condenser lens 40’, the footprint having a same or at least similar shape as the condenser lens 40 shown in Fig. 4a. The example presented in Fig. 5a defines a radius of curvature in X-direction, ROCXmarked as 48xto a value of 0. With an association of projection lens 26 as illustrated in Fig. 4b, image 47i generated with anamorphic surface 46i and / or image 472generated with anamorphic surface 462may exceed the possibly rectangular shaped exit micro lens 26. This may be addressed, for example, with a different distance between the lenses, the arrays, respectively or with a larger dimension of projection lens 26 or other measures.

[0069] In other words, Figs. 5a and 5b show a chevron-like entrance lenslet 40’ built of two mirrored cylindrical parallelogram-shaped lenslets 46i, 462and a schematic representation of the image of the source, e.g., a square LED, on the exit lenslet 26, leading to undesired crosstalk, see Fig. 5b.According to an embodiment, each of the anamorphic surfaces 46i and 462 may comprise a toroidal or biconical shape and / or may be shaped independently or differently from one another.

[0070] When compared to the embodiment presented in Fig. 5a and Fig. 5b that may be referred to a simple implementation, an intermediate implementation forming another example and relating to both of the parallelogram-shaped lenslets having a toroidal or biconical surface that are rotated under a certain angle, the following may apply. In the mentioned case, the condition of fully jumpless arrangement may be interpreted as having the same sag between points II and T as well as between points P and Q, wherein the sag may be but is not required to be equal for all four points. Due to a symmetry, when being the same for II and T and, thus, for U1 and T1, a corresponding adjoining region formed, e.g., in the arrangement of Fig. 4b, leads to a jumpless arrangement as well as when having a same sag on points P and Q that may be part of an adjoining region along an orthogonal direction. This can be achieved with a certain combination of chevron angle a, surface rotation and

[0071] R0CY

[0072] m = - ROCX

[0073] which denotes a ratio between radii of curvature of the anamorphic surface. For simplicity of explanation, a conic constant is chosen to be zero, however, the below-mentioned solutions hold true for non-zero conic values, especially as long as conic is the same in X and Y directions. It is preferred to keep conic equal to zero in both directions, as long as the numerical aperture, NA, of entrance lenslet is smaller than 0.1. When the entrance lenslet’s NA > 0.1, conic should be applied, i.e., the conic constant is preferred to be different from zero.

[0074] Further, the adapted height profile may be implemented for more than two, in particular a plurality or even all condenser lenses of the condenser lens array, wherein a single condenser lens may have adjoining regions with more than one, e.g., at least two, at least three, at least four or even more lenslets, e.g., when using irregular pentagons, hexagons and the like. An adaptation of height profiles may be realized at more than one or even all of the adjoining regions. For example, a condenser lens being sandwiched or arranged between two other, a second and a third condenser lens of the array, may provide for in total, a first, second and third condenser lens (and further) that adjoin in a first adjoining region and a second adjoining region. Optionally, a height for the first condenser lens isdifferent at the first side and at the second side and adapted to the second condenser lens at the first adjoining region and adapted to the third condenser lens at the second adjoining region. In other words, the height or sag of the lens is not required to be of a same value or symmetric on two or more sides of the lens such that, for example, and by making reference to Fig. 8a, sag values, e.g., on a positive and a negative side of the x-axis of a lenslet that may differ from one another.

[0075] To achieve completely sag height jumpless solution, ratio between radii m can be calculated as:

[0076]

[0077] as well as the rotation of the anamorphic surface ft may be adjusted according to:

[0078] B = 90 — arccosK

[0079]

[0080] The evaluation of the sag at the specific X-Y coordinates, e.g., at the corners of the parallelogram-shaped aperture, can be done using the known sag equation for biconical surfaces:

[0081]

[0082] where: z denotes the surface sag; cxdenotes the curvature in X direction; cydenotes the curvature in Y direction; kxdenotes the conic constant in X direction and kydenotes the conic constant in Y direction.

[0083] For the calculation of the sag of the rotated biconical surface, the rotated coordinates can be applied as follows:

[0084] x'(x,y, ) = x cos(B) — y sin(B)

[0085] y'(x,y,( ) = x sin(J3) + y cos(J3)where: x & y- initial point coordinates; x’ & y’ - new point coordinates with rotation of the biconical surface / 3 applied;

[0086] Naturally, the case of m = 1 can be excluded, as it leads to simple non-anamorphic surface of the lenslet, which cannot have equal sag between aforementioned points within the parallelogram-shaped aperture. It is preferred to choose relatively small values for a, possibly but not necessarily being, within a tolerance range of e.g., 15 %, 10 % or 5 %, at most 35° (e.g., 25° in the given example). A small value of a may allow m to be as close to 1 as possible, which improves the imaging property of the entrance lenslets.

[0087] Alternatively, if one aims for the concrete relation between the radii, then the possible maximum for chevron angle a can be calculated as follows:

[0088] a = arctan

[0089]

[0090] The imaging properties of the complete chevron-like freeform lenslet, which may comprise or consist of two anamorphic sub-lenslets designed as described above, also depends on the choice of the vertex position within the aperture. The examples given in Fig. 4a-6b show the case, where the vertex is present for each of the two sub-lenslets, however embodiments also relate to cases where a better imaging of the pre-collimated light source by the full chevron-like entrance lenslet is achieved, when the vertex position is common for both of the sub-lenslets as shown in Fig. 6c-d. Nevertheless, the choice of the vertex I vertices position is free and doesn’t affect the jumpless arrangement as long as it’s done symmetrically between the sub-lenslets, anamorphic surfaces 48.

[0091] The described completely sag heigh jumpless solution may form one implementation of embodiments. However, from the complete jumpless solution, deviations also fall under the scope of the invention as described herein, e.g., making reference to Fig. 2.

[0092] In Fig. 6a, there is shown a schematic top view on a footprint of a condenser lens 40” that may be used in an optical beamformer according to an embodiment. The anamorphic surfaces 48i and 482 may each comprise a vertex 52i, 522, respectively being located, for example, in a region of a center of the respective anamorphic surface 48i, 482, respectively, leading to separated images 47i and 472 in the illustration of Fig. 6b.Fig. 6c shows a schematic top view on a footprint of a condenser lens 40”’ that may be used as a condenser lens in an optical beamformer according to an embodiment. As noted, within a same condenser lens array 16, being described, e.g., in Fig. 1a, the condenser lenses may have a same or different shape which also relates to a position of vertices 52i and 522 when implementing the example chevron-shape. That is, different condenser lenses may be implemented thereby forming, e.g., a combination of condenser lenses 40” and 40”’.

[0093] In the example presented in Fig. 6c, the respective vertex 52i and 522of anamorphic surfaces 48i and 482is located at the adjoining region between the sub-lenslets 48i and 482represented as a line 54 between points P and Q. More specifically, vertices 52i and 522may be arranged close to one another or even at a same point on the line 54 which may allow to join images 47i and 472as shown in the corresponding illustration of Fig. 6d.

[0094] In other words, Fig. 6a shows a chevron-shaped entrance lenslet40” with individual vertices 52i and 522of two sub-lenslets 48i and 482. Fig. 6b shows a corresponding schematic representation of the image of the source, e.g., a square LED, on the exit lenslet 26. Fig. 6c shows a chevron-shaped entrance lenslet 40’” with a common vertex of two sub-lenslets 48i and 482and Fig. 6d shows a corresponding source image.

[0095] To avoid undesired cross-talk, embodiments implement an accurate selection of the position of the vertex I vertices, and / or of a distance between entrance and exit lenslet planes in such a way, preferably such that the image of the pre-collimated light source is kept within the single channel, see Fig. 7a and Fig. 7b showing a respective front view on an exit microlens plane. In several embodiments, especially with m « 1, optimization of the distance between entrance and exit lenslets is of specific advantage or may even be required - to achieve an optimum position, where the extent of the beamlet is the smallest for the given ROCx and ROCY. In connection with embodiments, a beam, e.g., of light, may be understood as a light cone obtained by an array of lenses described herein. A beamlet may be understood as light that passes through a single channel. That is, a beam may be a total light cone that exits the complete array, while a beamlet may be understood as a single light cone, which exits only one channel.

[0096] In other words, embodiments may be related to an optimization of a distance between entrance or condenser lens and exit or projection lens for finding a compromise between X and Y source imaging. Fig. 7a shows a distance being not optimized and Fig. 7b shows adistance being optimized, wherein the images of the source are represented only schematically.

[0097] A width (W) and / or a height (H) of the chevron as presented in Fig. 4a does not affect the jumpless arrangement, as long as the chevron angle a is not changed. Therefore, the choice of the specific values for W and H is a degree of freedom, considering the required extent of the exit lenslet to be sufficient enough to cover the image of the pre-collimated light source entirely within itself, see Fig. 6b and Fig. 6d. Such a design approach being described above is now illustrated for a chevron with a width of example W = 0.70 mm and height H = 0.35 mm and angle a being 25°.

[0098] The surface of one or each of the example entrance sub-lenslet is a toroidal surface with m ~ 0.40 and rotation / 3 » 55°, see Fig. 4a. A sag distribution map shown in Fig. 8a and a schematic 3D appearance of the array built from the resulting chevron-shaped entrance lenslets is shown in Fig. 8b. The modelling of the entrance micro-lens array is performed with consideration of the typical manufacturing constrains to trustfully consider the influence of the interlenslet regions on the straylight [6], It can be seen that there are no sag height jumps between adjacent lenslets.

[0099] In other words, Fig. 8a and Fig. 8b show a sag distribution map, see Fig. 8a, and a 3D appearance of the sag jumpless array built from freeform chevron-shaped entrance lenslets, Fig. 8b.

[0100] The exit array or projection lens array may be made from rectangular exit lenslets, but they can also have same chevron-like shape, e.g., to follow the shape of the condenser lenses. However, it is advised to choose the footprint of the exit lenslet according to embodiments and in such a way, that it fully encloses the image of the pre-collimated light source, built by the chevron-shaped entrance lenslet on the plane of the exit lenslet. The resulting projected pattern at 2 meters is shown in Fig. 9. It can be seen that there are no localized straylight lines around the projected pattern, which is the result of the sag height jumpless arrangement.

[0101] In other words, Fig. 9 shows a resulting projected pattern on a screen in a distance of 2 meters with a single pre-collimated light source applied wherein a logarithmic scale 56 relating to an incoherent illuminance shows the high quality of the pattern.More than one of such patterns can be generated with the same pattern generator or optical beam former, provided that additional pre-collimated light sources are used in the system with an oblique illumination angle. In this case the cross-talk can be utilized in a controlled manner to create the same pattern precisely adjacent to the original one or with a spacing [3], [4], By a corresponding control of all pre-collimated light sources in the system, the dynamic function can be achieved with projected patterns running in a sequence. Embodiments provide for an optical beam former or a projection device having an optical beam former comprising a control unit adapted to control the light source accordingly.

[0102] Further embodiments relate to sag height jumps suppression with polynomial freeform surfaces which may be referred to as an advanced case.

[0103] Making the surface of the sub-lenslet enclosed in the parallelogram-shaped aperture to be completely freeform. This can be achieved by optimizing the imaging of the entrance lenslet with additional criteria of the certain sag value to be achieved on the specific radial coordinates of the surface.

[0104] According to an embodiment the at least one of the condenser lenses used in an optical beamformer comprises two adjacent anamorphic surfaces each comprising a shape of a polynomial freeform surface. For example, such surface can be represented as Extended Polynomial surface type, where the sag at any radial coordinate can be calculated as:

[0105]

[0106] where: N denotes a number of polynomial coefficients in the series; A & E, denote coefficients on the ithextended polynomial term and r denotes a radial coordinate. This specific case may relate to a complete condenser lens, regardless whether it comprises a chevron shape or a different footprint, the condenser lens being realized as a freeform surface.

[0107] It may be preferred to use as little as possible number of polynomial coefficients during the optimization of the freeform surface to avoid sag oscillations. With high orders used it may be important to control the sag values not only at the corners of the aperture, but also within the lines connecting these corners, as sag might be distributed differently along two adjacent lines of two neighboring entrance lenslets (e.g., between lines TQ and UP inFig. 6a and / or Fig. 6c). As imaging optimization criteria a standard spot size can be chosen. Alternatively the total energy enclosed within the area of the exit lenslet can act as optimization target. Advantageously, use of high order freeform surface can allow for more complex aperture shapes of the condenser lenslet, as long as it’s ensured, that the shape fulfils 100 % fill-factor of the condenser array or is at least close to 100 %.

[0108] A design example for such an approach described is given for the entrance lenslets having more complex aperture shape with 8 corners as shown in Fig. 10a-b illustrating another irregular formed footprint of condenser lenses 40””. A single lenslet 40”” may be considered as a combination of one rotated toroidal surface and two spherical surfaces shifted vertically towards opposite directions, which may ensure the absence of sag height jumps between resulting lenslets while forming an array. In Fig. 10a there is shown a sag distribution map and in Fig. 10b there is shown a 3D appearance of the sag jumpless condenser lens array having a plurality of condenser lenses 40””, each built from freeform entrance lenslets with complex aperture shape with 8 corners.

[0109] In this particular case, due to step-like structure of the resulting entrance array, exit lenslets may preferably be arranged in the same way as shown in Fig. 11a illustrating a schematic perspective view of an projection lens array 24’ having a plurality of projection lenses 26’. To preserve a high quality or even the best imaging of the pattern, profile of exit microlenses may be kept as simple spherical or aspherical surface, therefore slight sag height jumps on the exit side are inevitable but acceptable. Typically, sag height jumps on the exit side are significantly less critical than on the entrance side, because they do not result in localized straylight features in the far-field [6], The resulting projected pattern at infinity is shown in Fig. 11b showing also a luminous intensity scale. It can be seen that there are no localized straylight lines around the projected pattern, which is the result of the sag height jumpless arrangement of entrance lenslets. That is, Fig. 11a shows a schematic perspective view of an exit lenslets array according to an embodiment and Fig. 11b shows an illustration of a resulting pattern projected at infinity with a single pre-collimated light source applied.

[0110] Similarly, other complex shapes of the pattern (e.g., with more corners or with smooth curved lines) can be achieved by optimizing the freeform profile of entrance lenslets for the trade-off between the sag height jumps and the quality of the source images on the exit array plane. The requirement for the cross-talk free system is that the total geometrical extent of the source image built by freeform entrance lenslet has to be kept withing theaperture of the corresponding exit lenslet. Finally, controlled cross-talk may be still applied to produce more than single pattern with the same projection system.

[0111] Whilst, as described for the chevron-like structure, embodiments may relate to a use of two anamorphic surfaces comprising a shape according to two anamorphic surfaces comprising a shape according to:

[0112]

[0113] with m indicating a ratio between different radii of the anamorphic surfaces (46i, 462) along orthogonal directions x and y; a being a chevron angle;

[0114] B = 90 — arccos

[0115]

[0116] with p indicating a rotation angle by which the anamorphic surfaces are rotated; or

[0117]

[0118] For the same, i.e., chevron-shaped or for other surfaces, there might be applied, according to embodiments, an implementation of one or more condenser lenses, comprising at least two adjacent anamorphic surfaces, each comprising a shape according to wherein the first condenser lens comprises two adjacent anamorphic surfaces each comprising a shape according to:

[0119] >

[0120]

[0121] wherein N is a number of polynomial coefficients in the series; Ai & Ei are coefficients on the ithextended polynomial term and r is a radial coordinate of z indicating a surface sag, and c is a curvature value.In connection with a use of conical surfaces in any of the above cases or other cases, in general, and as a basis for such considerations, a layout of the lenslets may be based according to the following determination rule:

[0122]

[0123] with z indicating a surface sag, cxindicating a curvature of the anamorphic surface along direction x, Cy indicating a curvature of the anamorphic surface along direction y, kxindicating a conic constant in x direction; kyindicating a conic constant in y direction, and

[0124]

[0125] wherein x and y indicate initial point coordinates and x’ & y’ indicate new point coordinates with rotation of the biconical surface / 3 applied; or

[0126] a = arctan

[0127]

[0128] Whilst some embodiments of the present invention have been described to comprise the adjoining region to comprise a straight shape in a planar view, e.g., in connection with Fig. 3a, Fig. 4a, Fig. 5a, Fig. 6a, Fig. 6c, Fig. 8a and Fig. 10a, it is also possible to form the adjoining region to comprise a continuous, i.e., steadily formed shape or to comprise a shape corresponding to a periodic function such as a sine or cosine function. An example for a continuous or steadily formed adjoining region 28 is shown in Fig. 12, wherein the adaptation of the height profiles of condenser lenses 181 and 182may be in accordance, for example, with Fig. 2a and / or in accordance with a jumpless implementation.

[0129] Fig. 13 shows a schematic flow chart of a method 1300 according to an embodiment that may be used to determine properties and / or a shape of condenser lenses according to an embodiment. That is, method 1300 may be used to construct one or more condenser lenses. A step 1310 comprises determining a shape of a pattern to be projected by use of the plurality of condenser lenses. A step 1320 comprises determining a height profile of theplurality of condenser lenses such that the height profiles of each condenser lens are adapted to a respective adjoining condenser lens.

[0130] It is noted that it is possible to distribute condenser lenses in the condenser lens array differently and, e.g., by amending the projection direction of a projection lens or an optical channel thereof, a position of a condenser lens such that it is possible to adapt the height profile also by considering a changed location of optical channels that are intended to overlap at the projected image.

[0131] Embodiments of the present invention may be used for different applications. For example, embodiments may be used in automotive lighting and signaling, e.g., in static or dynamic projective turn indicators, in static or dynamic projective reverse driving indicators or an automotive low beam. Embodiments may also be used in different fields of application, e.g., in general lighting and projection applications such as a stage lighting and / or architectural or industrial illumination.

[0132] Embodiments described herein relate to adapting a height profile of adjacent condenser lenses to one another to avoid or limit jumps in the height profile. As shown in Fig. 4b, Fig. 8b, Fig. 10b and Fig. 11a, adjacent condenser lenses may have a similar or same shape, which may be a part of implementing the condenser lens array as a parquetted lens array. Such a parquetted lens array may result from partitioning the pattern to be projected as described, for example, in DE 102022210090 A1. Such partitioning may be used to avoid empty zones or dead zones between condenser lenses. Such avoidance of dead zones in connection with the requirements given by the desired or predefined pattern and in further view of the adapted height profile may cause mutual dependencies that may lead to restrictions with regard to the adaptation of the height profile.

[0133] In DE 102022210090 A1 a technique is presented that relates to a condenser lens array that has at least one cluster of condenser lenses, each condenser lens of the cluster having an aperture adapted to a sub-area of an overall pattern projected by the optical beam former in order to provide for the projection lens array a portion of the incident light beam that is associated with the subarea of the overall pattern, wherein a combination of the apertures of the condenser lenses is adapted to the overall pattern. Aspects thereof relate to realizing an intermediate region or intermediate area between apertures of adjacent condenser lenses of the cluster as a light-scattering region, e.g., as presented in Fig. 2 or Fig. 4a-b or Fig. 5a thereof, i.e., the adjacent condenser lenses sandwiching the intermediate regionmay have a same shape or different shapes. Further aspects thereof relate to realizing the light-scattering region as a diffuser, a concave lens, and / or a statistical surface scatterer. Such technique and aspects are also combinable to form a part of embodiments described herein, including the dependent aspects described in DE 102022210090 A1.

[0134] For example, when the adaptation of the height profile is not sufficiently realizable or would lead to other issues in the device, embodiments relate to implementing such intermediate regions, e.g., as diffracting or scattering region, e.g., between a subset individual lenses whilst adapting the height profile for other lenses; or to arrange the intermediate region between clusters of lenses according to DE 102022210090 A1. This may allow to avoid disturbances in the projection at the expense of accepting some loss of the lens array area, i.e., a decreased fill-factor. In simple terms, for at most a subset of sections or regions between adjacent lenses, e.g., where the adaptation of the height profile is not sufficiently realizable, an intermediate region or scattering region may be arranged to avoid unwanted degradation within the projection caused by the remaining height jumps. Such intermediate regions are advantageously but nevertheless optionally configured for a jumpless and / or gapless height adaptation between the adjacent condenser lenses. For example, a remaining height difference between the optical active surfaces of the condenser lenses might cause an almost vertical or perpendicular edge between the condenser lenses which might cause optical distortions. Such edges may be prevented by the intermediate regions that may level the height difference which may result in a comparatively flat transition between the condenser lenses when compared to the almost vertical or perpendicular edge. The intermediate regions may comprise a free-form layout or base area, e.g., based on the shape of the condenser lenses.

[0135] According to embodiments of the present invention, the adaptation of the height profile may be combined with intermediate regions, e.g., between usable condenser openings that cannot be designed to be gap-free, i.e., having an adapted height profile, or between usable condenser openings that cannot be tiled with a fill factor of approximately 100 %. These intermediate regions may have free-form surfaces that ensure a gap-free connection between the usable condenser openings. The intermediate free-form surfaces may be designed in such a way that they deflect the light passing through them away from the usable part of the projected pattern in a controlled manner, e.g., at large angles.

[0136] Further embodiments of the present invention relate to a projection device, possibly adapted in a specific application as described herein. Such a projection device comprises an opticalbeam former described herein and comprises a light source configured for providing the emerging light beam.

[0137] Although some aspects have been described in the context of an apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or device corresponds to a method step or a feature of a method step. Analogously, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus.

[0138] The above described embodiments are merely illustrative for the principles of the present invention. It is understood that modifications and variations of the arrangements and the details described herein will be apparent to others skilled in the art. It is the intent, therefore, to be limited only by the scope of the impending patent claims and not by the specific details presented by way of description and explanation of the embodiments herein.

Claims

25Claims1. An optical beam former for generating an emerging light beam (12) from an incident light beam (14), the optical beam former comprising:a condenser lens array (16) comprising a plurality of condenser lenses (18, 34, 40; 40’; 40”; 40”’; 40””), the plurality of condenser lenses (18, 34, 40; 40’; 40”; 40’”; 40””) configured for receiving the incident light beam; anda projection lens array (24) comprising a plurality of projection lenses (26) configured for receiving light from the condenser lens array (16) and for radiating the emerging light beam (12),wherein a footprint of at least a first condenser lens (34x) of the condenser lens array (16) comprises a non-rectangular shape; and wherein at an adjoining region (28) between the first condenser lens (34x) and an adjoining second condenser lens (34y) a height profile of the first condenser lens (34x) is adapted to the second condenser lens (34y).

2. The optical beam former according to claim 1, wherein the footprint is an irregular shaped footprint.

3. The optical beam former according to claim 1 or 2, wherein a footprint of the plurality of projection lenses (26) follows the footprint of the plurality of condenser lenses (18, 34, 40; 40’; 40”; 40’”; 40””).

4. The optical beam former according to one of previous claims, wherein for the adapted height profile the first or second condenser lens (34x, 34y) comprises a sag height jump of at most 30 % of a total sag profile height of the condenser lens (34).

5. The optical beam former according to one of previous claims, wherein each condenser lens of the plurality of condenser lenses (18, 34, 40; 40’; 40”; 40’”; 40””) comprises a footprint with a non-rectangular shape and comprises a height profile being adjusted with regard to an adjoining condenser lens in a respective adjoining region (28).

6. The optical beam former according to one of previous claims, wherein the adapted height profile is an essentially jumpless height profile between adjacent lenses of the plurality of condenser lenses (18, 34, 40; 40’; 40”; 40”’; 40””).

7. The optical beam former according to one of previous claims, wherein the adjoining region (28) comprises a straight shape in a plan view; or comprises a continuous shape or comprises a shape corresponding to a periodic function.

8. The optical beam former according to one of previous claims, wherein at least a subset of the plurality of condenser lenses (18, 34, 40; 40’; 40”; 40’”; 40””) comprises a congruent footprint, and / or are arranged as a cluster and comprise the adapted height profile within the cluster.

9. The optical beam former according to one of previous claims, wherein the second condenser lens (34y) adjoins the first condenser lens (34x) at the adjoining region (28) being a first adjoining region and at a first side of the first condenser lens (34x);wherein a third condenser lens of the plurality of condenser lenses (18, 34, 40; 40’; 40”; 40’”; 40””) adjoins the first condenser lens (34x) at a second adjoining region arranged at a different second side;wherein a height profile of the first condenser lens (34x) is different at the first side and at the second side and adapted to the second condenser lens (34y) at the first adjoining region; and adapted to the third condenser lens at the second adjoining region.

10. The optical beam former according to one of previous claims, wherein at least a subset of the plurality of condenser lenses (18) comprise a footprint having a chevronshape.

11. The optical beam former according to previous claims, wherein the chevron-shape comprises two, preferably exactly two anamorphic surfaces (46i, 462) rotated within a parallelogram aperture.

12. The optical beam former according to claim 11, wherein the anamorphic surfaces (46i, 462) comprise a toroidal or biconical shape.

13. The optical beam former according to claim 11 or 12, wherein the two anamorphic surfaces (46i, 462) comprise a shape according to:with m indicating a ratio between different radii of the anamorphic surfaces (46i, 462) along orthogonal directions x and y; a being a chevron angle;B = 90 — arccoswith p indicating a rotation angle by which the anamorphic surfaces are rotated; org = arctan14. The optical beam former according to one of previous claims, wherein the first condenser lens (34x) comprises two adjacent anamorphic surfaces (46i, 462) each comprising a shape of a polynomial freeform surface.

15. The optical beam former according to one of previous claims, wherein at least one or each condenser lens (18, 34, 40; 40’; 40”; 40”’; 40””) is associated with exactly one projection lens (26); and / or wherein at least one condenser lens (18, 34, 40; 40’; 40”; 40’”; 40””) is associated with more than one projection lens (26).

16. The optical beam former according to one of previous claims, wherein at least a subset of the plurality of condenser lenses(18, 34, 40; 40’; 40”; 40’”; 40””) comprise a footprint having a free-form profile.

17. The optical beam former according to one of previous claims, wherein a shape of the first condenser lens (34x) comprises a rounding in the adjoining region (28) that28comprises a radius (r) of at most 15 % from a total extension of the condenser lens (34x) along a direction from a center of the first condenser lens (34x) to a center of the second condenser lens (34y) to comply with the adapted height profile.

18. The optical beam former according to one of previous claims, wherein the adjoining region (28) comprises a lateral extension along a direction from the first condenser lens (34x) to the second condenser lens (34y) that is at most 15 % from a total extension of the condenser lens along a direction from a center of the first condenser lens (34x) to a center of the second condenser lens (34y) to comply with the adapted height profile.

19. The optical beam former according to one of previous claims, wherein a sag height jump flank (44) between the first condenser lens (34x) and the second condenser lens (34y) is inclined by an angle of at least 60° with regard to a surface of a substrate carrying the plurality of condenser lenses (18, 34, 40; 40’; 40”; 40”’; 40””) to comply with the adapted height profile.

20. The optical beam former according to one of previous claims, comprising an intermediate region between adjacent condenser lenses (18, 34, 40; 40’; 40”; 40’”; 40””) of at most a subset of the condenser lenses (18, 34, 40; 40’; 40”; 40’”; 40””) with an unadapted height profile.

21. The optical beam former according to claim 20, wherein the intermediate region comprises a light-scattering region, e.g., comprising a diffuser, a concave lens, and / or a statistical surface scatterer.

22. The optical beam former according to claim 21, wherein the the intermediate region is configured for a jumpless and gapless height adaptation between the adjacent condenser lenses.

23. The optical beam former according to one of previous claims, wherein a fill-factor of the plurality of condenser lenses(18, 34, 40; 40’; 40”; 40’”; 40””) in the condenser lens array (16) is at least 85 %.2924. The optical beam former according to one of previous claims, wherein a shape of the footprint of the condenser lenses (18, 34, 40; 40’; 40”; 40”’; 40””) corresponds to a shape of a pattern projected by use of the projection lens (26).

25. Projection device comprising:an optical beam former according to one of previous claims, anda light source configured for providing the incident light beam (14).

26. Method (1300) for constructing a plurality of condenser lenses, comprising:determining (1310) a shape of a pattern to be projected by use of the plurality of condenser lenses; anddetermining (1320) a height profile of the plurality of condenser lenses such that the height profiles of each condenser lens are adapted to a respective adjoining condenser lens.

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