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?
The sensor is like a small dot, usually located on the left of the HTC logo, above your device's screen. Also the location of the proximity sensor is.
FYI: HTC ONE models S, X, V, EVO 4G LTE are very much alike in physical conception.
This is covered at XDA Developers forum thread: Where is the One X's ambient light sensor?

By Tiersten:
Left of the HTC logo above the screen. It is also where the proximity sensor is.
By jaaystott:
If you call someone, take a look at the front of your phone. You will see a steady red glow from the top left of your screen, this is where the proximity and ambient light sensor are housed.


Additionally, there's this White Paper: Ambient Light Sensor (ALS) Applications
in Portable Electronics that shows their physical aspect: