Etendue conserving light shaping using microlens arrays with irregular lenslets

Li, Chen; Schreiber, Peter; Michaelis, Dirk; Wächter, Christoph; Fischer, Stephanie; Zeitner, Uwe D.

doi:10.1117/12.2313803

Cited by 5 publications

(5 citation statements)

References 1 publication

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“…The design procedures to find the correct aperture sizes and decentrations to generate a desired distribution have been described before. [5,6] As stated above every lenslet column creates a projected column in the far field. Thus, the vertical profile of a given column only applies to a certain part of the horizontal field of view, giving the possibility to vary the vertical cross-section over the horizontal extent of the beam.…”

Section: Mla Designmentioning

confidence: 98%

Design of maskless micro-optical automotive low-beam

Wilhelm,

Stefanidi,

Schreiber

et al. 2024

Optical Design and Engineering IX

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Recently the first automotive vehicles with micro-optical headlights entered the market as series production models. Besides aesthetics, multi aperture micro-optics bring the advantage of a reduced axial length of the system due to the much shorter focal length of each channel. However, the currently implemented low-beam systems suffer from low transmission and notable cost for the micro-optics elements. Both problems can be traced back to the buried micro-slides within the micro lens arrays, (MLA) which shape the distribution. To overcome these issues, we developed a micro-optical solution for a low-beam without mask layers, thereby significantly increasing transmission to a very competitive level and enabling more cost-effective manufacturing processes. Our design follows the general principle of a fly's eye condenser (FEC) but comprises of a multitude of differently shaped lenslets, which form the beam collectively. The design process includes the generation of the overall distribution as well as detailed features such as the sharp and specially shaped cut-off and a smooth distribution within the beam. Particular effort is necessary to control stray light which is caused by imperfect manufacturing of the MLAs. A first LED-illuminated demonstrator showed that the shape and the required sharpness of the cut-off can be achieved even without the use of absorbing masks with a single optical module. Stray light control and fine tuning of the distribution makes it possible to manufacture a maskless polymer-on-glass micro-optical component and generate a beam pattern in accordance with UNECE safety regulations.

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Section: Mla Designmentioning

confidence: 98%

Design of maskless micro-optical automotive low-beam

Wilhelm,

Stefanidi,

Schreiber

et al. 2024

Optical Design and Engineering IX

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“…Intentional crosstalk is generated by off-axis illumination of the MLA, leading to imaging of each condenser lenslet by projector lenslets of neighbored channels as described by the schematic in Figure 7 (right). MLAs utilizing intended ondenser rojector th order nd order nd order crosstalk have been previously used to generate light distributions for segments of an adaptive high beam for automotive applications [8].…”

Section: Design Examplementioning

confidence: 99%

Multi-aperture pattern projection using arbitrary shaped microlenslets

Kundu,

Michaelis,

Schreiber

et al. 2023

Current Developments in Lens Design and Optical Engineering XXIV

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Micro-optical projectors consist of a double-sided, aligned microlens array (MLA) with an absorptive slide mask array buried under the entrance condenser lenslets. While the exit lenslets project the slides, the condenser lenslets realize Kohler illumination of the multiple projector channels. To achieve high system transmission, the condenser lenslets have to be positioned in a space-filling arrangement. For arbitrary projected shapes, the slide further reduces the effective fill-factor of a channel.We propose to increase fill-factor and simplify architecture of the MLA by replacing the buried slides by condenser lenslets with certain elementary shapes, building an irregular entrance array with space-filling parqueting. The condenser lenslets´ apertures are imaged by the projector lenslets towards certain positions in the far-field, controlled by the decentration between condenser contour and projector vertex. This enables for optional 'jigsawing' of the intended pattern from elementary images.Any residual MLA regions, that cannot be covered by condenser lenslet apertures, can be excluded from projection by patterning with diffusor structures, which scatter away incident light under large angles. Now, that we have excluded the buried mask array, such double-sided MLA can be replicated not only as precise polymer-on-glass elements (POG), but also by cheaper high-volume techniques like injection molding (IM), making the latter attractive for the automotive industry.An automotive projecting chase light blinker based on this concept, employing controlled channel crosstalk, replicated as POG is presented. IM replication of MLA is currently underway. We evaluate the performance and present a brief outlook of mask-less, multi-aperture microoptics.

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“…However at that time, diffractive optics were not able to fulfil many of the high-flying expectations. Nevertheless, since then substantial improvements of the fabrication technologies specifically dedicated to the realization of optical micro-and nano-structures have brought such elements into a multitude of applications [2][3][4][5][6][7]. A particularly topical area of research in this context is the field of optical meta-materials, as they offer access to novel optical functionalities by nano-patterning [8].…”

Section: Introductionmentioning

confidence: 99%

The potential of e-beam lithography for micro- and nano-optics on large areas

Zeitner

Banasch

Trost

2023

Novel Patterning Technologies 2023

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The availability of high-resolution and high throughput lithographic fabrication technologies such as electron-beam lithography based on Variable Shaped Beam writing and Character Projection opens the way for the flexible use of various optical nano-structures for some of the most demanding applications. The paper discusses the technical features, advantages, and limitations of these pattering approaches and will show how they can favorably be combined to realize optical nano-structures for applications, which are as diverse as gratings for ultra-short laser pulses or high resolution spectrometers, computer generated holograms for asphere testing, various optical meta-structures (lenses, gratings), or UV-polarizers.

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Etendue conserving light shaping using microlens arrays with irregular lenslets

Cited by 5 publications

References 1 publication

Design of maskless micro-optical automotive low-beam

Design of maskless micro-optical automotive low-beam

Multi-aperture pattern projection using arbitrary shaped microlenslets

The potential of e-beam lithography for micro- and nano-optics on large areas

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