What are those glasses that show ROYGBIV called?

10
0
It's really bothering me, since the name is like on the tip of my tongue.
 
Diffraction grating glasses?
 

The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top