I'm running on the assumption this is the machine booting, and therefore before the OS has loaded.
Looks like your laptop panel has failed or received damage, especially if you are getting a correct video output from an external screen. It is also possible the cable has been damaged, they can get caught in hinges, or become loose.
You could try checking the integrity of the cable and re-seating it. If this appears okay, to test the panel you would need to get the panel replaced. These are usually fairly generic but there are some exceptions (LCD panels will have a backlight and an inverter which may have custom connectors/two backlight bulbs. LED panels have no inverter, so you must use the correct type of panel).
Your best bet is to take it to a reputable shop for them to test another panel in and replace if required, as depending on the laptop model this can be quite a tear-down.