# Optomechanical Analysis and Design of Polygon Mirror-Based Laser Scanners
## 7 Conclusions  
Characteristic functions and parameters of PM scanning heads were deduced. Their multi-parameter analysis and design were developed, considered in contrast to the more common GSs. PMs are characterized by a larger number of parameters than GSs, and this complicates the mathematical discussion, but also provides more degrees-of-freedom in the design process of PM-based scanning heads. Furthermore, PMs are driven by fast rotational motors, with common rotational speeds \(\omega\) of 54 krpm, and up to 70 krpm, while velocities of 120 krpm are envisaged in the context of the development of appropriate sensors and control structures that may be able to provide rotational velocity uniformity of the PM shaft. Such a high \(\omega\) requires performing an FEA of the rotational PM to assess the structural integrity. This study completes such a dual, opto-mechanical approach by proposing a designing scheme that includes both aspects, with their characteristic links.  
Rules-of-thumb were extracted from both the analysis of optical aspects and the FEA to design PM scanning heads by choosing or calculating their constructive and functional parameters. The deduced and analyzed characteristic functions are appropriate for a variety of such scanners [2]: Macro and micro, prismatic or pyramidal, normal or inverted, single- or double-pass, with simple or double [27] PMs. Furthermore, a range of applications can benefit from the developed theory, from industrial (for example, optical metrology and laser manufacturing, the latter including 3D printing) to high-end (for imaging using, for example, OCT or CM, but also for Remote Sensing).  
Aspects of PM scanning heads that may benefit from the developed theory include the ability (i) to obtain optimized 2D scanning heads with PM plus GS; (ii) to design more efficient SSs for OCT and (iii) handheld laser scanning probes; (iv) to carry out FEA and thus to optimize different PM configurations; (v) to consider tolerances and errors in analyses in relation to manufacturing methods; (vi) to develop more performant control structures to support higher rotational velocities of PMs (in an effort similar to the development of GSs); and (vii) to develop PM-type MEMS, a solution that can be more versatile with a larger FOV than resonant scanners.  
Conceptualization, methodology, and theory, V.-F.D.; two-mirror device, M.-A.D., V.-F.D.; FEA, V.-F.D.; writing--original draft, V.-F.D. and M.-A.D.; writing--review and editing, V.-F.D.; funding, supervision, and project administration, V.-F.D. All authors have read and agreed to the published version of the manuscript.  
This research was supported by the Romanian Ministry of Research, Innovation, and Digitization, CNCS/CCCDI-UEFISCDI, project PN-III-P4-ID-PCE-2020-2600, within PNCDI III ([http://3 om-group-optomechatronics.ro/](http://3 om-group-optomechatronics.ro/), accessed on 1 May 2022).  
Previous support for the initial FEA of PMs includes the US Department of State through the Fulbright Senior Research Grant 474/2009. The support of the host scientist, Professor [PERSON], is therefore gratefully acknowledged.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.