What does the ambient light sensor look like?

Naive question, but when I check the specs of a phone, one website says phone has feature X, the other says it does not have this feature. Here I am interested in the ambient light sensor. What does it look like, and where it is usually placed? **For example**, GSM Arena review says the HTC One V has an ambient light sensor: "Above the display is the earpiece alongside some hidden proximity and ambient light sensors." The photo: For comparison the text says I should see the proximity sensor too. On my Galaxy Ace 2 it looks like 2 mini cameras, it is hard to miss, and on that picture I don't see anything like that. Of course maybe HTC hid that all so well. Anyway, I would like to know what I am looking for, thus the question -- **What does the ambient light sensor look like?**