表面と裏面、表面、裏面

基板の表面と裏面。

ChatGPT:

The front surface and the back surface of the substrate.

Alternatively, depending on the context, you can also say:

• The top surface and the bottom surface of the substrate.
• The obverse surface and the reverse surface of the substrate. (Less common, but precise in some technical contexts.)

あなた:

How about "upper" and "lower" surfaces?

ChatGPT:

"Upper surface" and "lower surface" can be appropriate if the orientation of the substrate is fixed and the context clearly defines what is considered "upper" and "lower." However, in general descriptions, "front surface" and "back surface" (or "top surface" and "bottom surface") are more commonly used because "upper" and "lower" can imply a specific orientation, which may not always be relevant.

Would you like a translation that is more precise for a specific context?