MEMS piston mirror arrays for computer generated holography

Dürr, Peter; Neudert, Andreas; Nitzsche, M.; Hohle, Christoph; Stolle, Hagen; Pleikies, J.

doi:10.1117/12.2608081

Cited by 11 publications

(18 citation statements)

References 2 publications

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“…In our opinion, an electrostatic comb drive actuator is the best approach for reaching the challenging specifications shown above. As discussed in [3], a parallel plate actuator would not be suitable. In Figure 1 the design shows two straight hinges (blue), the fixed stator plane that is common for all pixels within the array (orange) and the movable yoke in green.…”

Section: Previous Comb Drive Actuator Designmentioning

confidence: 99%

“…As discussed in [3] the comb drive design has a strongly concentrated electrostatic field between the comb fingers which results in rather large forces for small pixels in combination with a potentially low crosstalk between neighbor pixels. This is essential for reaching the desired precision of deflection.…”

Section: Previous Comb Drive Actuator Designmentioning

confidence: 99%

“…Independent from the used principle (regular or complex) of modulation a very high degree of precision has to be achieved with high speed. Within the EU-funded project REALHOLO, Fraunhofer IPMS and its partners are developing an innovative SLM for holographic displays, see [3] and [5]. The combination of the very small pixel pitch, the high stroke, the extreme precision [2] and the high speed, results in very challenging electrical and mechanical requirements.…”

Section: Introductionmentioning

confidence: 99%

“…To fulfill these requirements the design needs as much headroom as possible from any point of view. The general concept and aspects like stability were already discussed in previous papers [3] with the outcome that the countermeasures for improving the general behavior come at the cost of a reduction of the electrostatic force which is available for the modulation.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Improved comb drive design for MEMS piston mirror arrays

Nitzsche¹,

Duerr²,

Neudert³

2023

MOEMS and Miniaturized Systems XXII

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MEMS (micro electro mechanical system) based piston mirror arrays are key elements for real time computer generated holograms (CGH) in visualisation technologies like virtual, augmented and mixed reality (VR/AR/MR). The EU funded Project REALHOLO is developing a spatial light modulator (SLM) that is based on comb drive MEMS actuators that can fulfil the tight requirements of the optical and mechanical performance and the high level of integration. A previous design already outlined perspectives for a superior performance in comparison to other approaches for high frequency and high precision wave front modulation, but has restrictions due to the resolution and feature size of the i-line lithography system used for manufacturing. This paper discusses the optimisation of the design applying an advanced manufacturing process using DUV lithography that allows smaller features and therefore offers additional design options. By introducing an improved comb drive geometry the electrostatic force was significantly increased, which allowed the optimisation of other geometries, like horizontal and vertical gaps and additional shielding structures, for an even more linear actuator response and reduced crosstalk. The electrostatic and structural FEM simulations will show the significant improvements in overall performance, compared to the previous iteration and other types of SLMs. The improved actuator can potentially extend the field of application from the desired automotive driver assistance holographic 3D display to head mounted displays for VR, AR and MR applications as well as other technologies like material processing.

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Section: Previous Comb Drive Actuator Designmentioning

confidence: 99%

Section: Previous Comb Drive Actuator Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Improved comb drive design for MEMS piston mirror arrays

Nitzsche¹,

Duerr²,

Neudert³

2023

MOEMS and Miniaturized Systems XXII

Self Cite

View full text Add to dashboard Cite

show abstract

“…Within the EU-funded project REALHOLO we are developing an innovative spatial light modulator (SLM) for holographic displays, see [2] and [3]. Micro-opto-electro-mechanical system (MOEMS) like this require sophisticated nonstandard packaging schemes in order to fulfil various goals:…”

Section: Introductionmentioning

confidence: 99%

FEM simulations to optimize a micro mirror array package for a wide operating temperature range

Dürr¹,

Guru²,

Mai³

2023

MOEMS and Miniaturized Systems XXII

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The package of a Micro-Opto-Electro-Mechanical System (MOEMS), a Micro Mirror Array (MMA) based Spatial Light Modulator (SLM), has to stay stable over the full operation temperature range and throughout SLM lifetime in spite of the inevitably different coefficients of thermal expansion (CTE) of the various materials involved. Additionally, in our case the window not only protects the MMA from mechanical damage and corrosion but also serves an optical function as part of a beam combiner. Within the European Union funded Project REALHOLO we are therefore developing a packaging concept that accomplishes the desired optical functionality while meeting the challenge of precise alignment of the window relative to the micro mirrors in lateral direction, which is the motivating factor behind the FEM simulations presented here. The objective of this research is to stabilize the package when subjected to temperature changes by simulating its thermomechanical behaviour with Ansys Workbench TM . A heatsink, a silicon crystal-based MEMS chip, and a window are glued together to form the package. Materials used for window and heatsink components, respectively, are chosen for a best possible CTE match. The significant parameters to be considered for package optimization are the misalignment between window and chip, the stress induced in the package, especially the glue, and the global deformation of the MMA surface. This paper discusses the challenges and possible solution based on a series of simulation findings.

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A new fabrication method for enhancing the yield of linear micromirror arrays assisted by temporary anchors

Xiao,

Mao,

Shi

et al. 2024

Microsyst Nanoeng

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As one of the most common spatial light modulators, linear micromirror arrays (MMAs) based on microelectromechanical system (MEMS) processes are currently utilized in many fields. However, two crucial challenges exist in the fabrication of such devices: the adhesion of silicon microstructures caused by anodic bonding and the destruction of the suspended silicon film due to residual stress. To solve these issues, an innovative processing method assisted by temporary anchors is presented. This approach effectively reduces the span of silicon microstructures and improves the Euler buckling limit of the silicon film. Importantly, these temporary anchors are strategically placed within the primary etching areas, enabling easy removal without additional processing steps. As a result, we successfully achieved wafer-level, high-yield manufacturing of linear MMAs with a filling factor as high as 95.1%. Demonstrating superior capabilities to those of original MMAs, our enhanced version boasts a total of 60 linear micromirror elements, each featuring a length-to-width ratio of 52.6, and the entire optical aperture measures 5 mm × 6 mm. The linear MMA exhibits an optical deflection angle of 20.4° at 110 Vdc while maintaining exceptional deflection flatness and uniformity. This study offers a viable approach for the design and fabrication of thin-film MEMS devices with high yields, and the proposed MMA is promising as a replacement for digital micromirror devices (DMDs, by TI Corp.) in fields such as spectral imaging and optical communication.

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MEMS piston mirror arrays for computer generated holography

Cited by 11 publications

References 2 publications

Improved comb drive design for MEMS piston mirror arrays

Improved comb drive design for MEMS piston mirror arrays

FEM simulations to optimize a micro mirror array package for a wide operating temperature range

A new fabrication method for enhancing the yield of linear micromirror arrays assisted by temporary anchors

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