Possible dirt inside new Nokia Lumia 640 camera? But how?

[Black Panther]

Bought this cellphone new 5 months ago from a local establishment.
Today I noticed that there were 2 black spots always in the same place of the photos I took today.
I thought it was dust on the outside, but wiping didn't clear them up. They are even visible on the phone's display before I take the photo.
I checked the photos I had taken before and those black spots were not there 5 days ago.
The camera is sealed, in that it remains intact when you remove the back-cover to change sim card or add an SD card. If there got to be some dirt inside, I'd have to unscrew and dismantle the phone, and I won't do that since the phone is still under warranty...

Could it be dirt, and how could it have gotten inside?
Or is it a some defect?

Here's a photo I took of a white background where the black dots show up very clearly:

Spoiler

 

[lorraine walsh]

The dust particles ain't exactly under the camera lens, nor the camera unit. They are actually just under the piece of glass protecting the camera.
You can actually clean it yourself, after disassembling the phone (you can watch tutorial on youtube) and taking out the camera unit.
Hope it helps.

 

[Swamp Monster]

Or they could be damaged pixels on camera chip. But try to take it apart and clean the protective glass.

 

[Komshija]

This is a tricky, since many phone "manufacturers" are as*holes which illegally forbid users to freely operate their own devices. I don't know how your device looks from the inside, but there might be certain stickers or some other kind of "protections" which even forbid users to properly clean their phones as long as the warranty lasts.
Check whether there really is some dirt under the camera glass.

 

[Ferrum Master]

I'd have to unscrew and dismantle the phone, and I won't do that since the phone is still under warranty...

It is on the sensor die itself, don't do anything. The camera needs to be exchanged - to the repair center.

 

[Black Panther]

It is on the sensor die itself, don't do anything. The camera needs to be exchanged - to the repair center.

That's what they did in fact. I took it for RMA and they replaced the entire camera unit.
Still funny though how come those 2 spots came there out of nowhere.

 

[Frick]

This is a tricky, since many phone "manufacturers" are as*holes which illegally forbid users to freely operate their own devices. I don't know how your device looks from the inside, but there might be certain stickers or some other kind of "protections" which even forbid users to properly clean their phones as long as the warranty lasts.
Check whether there really is some dirt under the camera glass.

Considering you generally have to use a heating gun, that kind of voiding warranty is something I actually agree with.