The lighting device includes a beam splitter, wherein the beam splitter includes an optically relevant aperture edge for generating a light-dark boundary.

Eine kleine Auswahl möglicher Übersetzungen:

Replacement Sealed Beam Bezel
https://shop.yamaha-motor.co.nz/accessories/road/road/cruise...

This is the Superbeam extra bezel which just screws on with a half turn
Standard 10w downlight comes with one lens to allow the light to omit around to give a halo effect
https://www.lumenlinks.shop/product-page/super-beam-bezel

Emblem Deutz Agrotron Main Beam Dip
https://www.tracteile.de/Emblem-Deutz-Agrotron-Main-Beam-Dip

sunshade | die Sonnenblende pl.: die Sonnenblenden
sun shield | die Sonnenblende pl.: die Sonnenblenden
sun visor [AUTOM.] | die Sonnenblende pl.: die Sonnenblenden
https://dict.leo.org/german-english/Sonnenblende

Here you will find valuable information and useful tips on the subject of light distribution for dipped beam, main beam and country road lighting.
https://www.hella.com/techworld/uk/Technical/Automotive-ligh...
Hier finden Sie wertvolles Wissen und nützliche Tipps rund um das Thema Lichtverteilung beim Abblendlicht, Fernlicht und Landstraßenlicht.
https://www.hella.com/techworld/de/Technik/Beleuchtung/Licht...

The technology that aims the beam and gives the LH or RH dip is designed into the complex multifaceted reflector. This Freeform light looks very good and performs very well - giving a good light output and dipping pattern. WITH BULB SHIELD.
https://www.s-v-c.co.uk/products/s6074-7-wipac-freeform-head...

The invention relates to a halogen incandescent lamp, which substantially comprises a lamp bulb, a dipped beam shield, three supporting pins and two incandescent filaments, the interior of the lamp bulb being filled with a halogen-containing gas and at least one supporting pin being welded to the dipped beam shield.
https://www.quickcompany.in/patents/halogen-filament-lamp-co...

14 Primary divergence and beam mask-slit limits irradiated area with a divergent X-ray source (Horizontal system viewed from above)
https://www.researchgate.net/figure/Primary-divergence-and-b...

Figure 6.8 Schematic diagram showing major components of a horizontal laboratory-type focusing System
Beam mask
https://www.researchgate.net/publication/42795493_Determinat...