faceplate

Short definition from Wiktionary

Noun

1. 1
   A removable protective shield separating the inner workings of a machine from operator and observer.
2. 2
   A rigid flat surface that has an active role in the interaction of a device with an operator or user.
3. 3
   A transparent window forming part of a helmet directly in front of the wearer's face, allowing them to see out.