gameplay-irrelevant question about digital indicator of CK-37

[Torbernite]

Just out of curiosity, which type of device is used as the digital indicator?

Visually it's not a rotation drum, not segment display like VFD or modern LCD.

I guess it's a series of Nixie tubes?

[MYSE1234]

Each digit is like a miniature projector kind of thing. No idea what they're called.

[Torbernite]

2小时前，MYSE1234说：

Each digit is like a miniature projector kind of thing. No idea what they're called.

Thank you! That's a genius design, I didn't even imagine it before.

[outbaxx]

One plane readout display
In-line digital display
IEE projection Display