Screen only works as normal when at some certain angles

From the 10.14 version, my macbook started to screen flickering, after a few days, the colour displayed on the screen became weird. I tried to reset SMC and NVRAM but it doesn't work. Then I reinstalled the system, the problem solved though.

Just recently my macbook starts flickering sometimes again and the colour becomes uncommon when it's not fully opened. So the colour only works as usual when screen is fully opened and when it's only opened a little bit. That's really annoying. Can somebody help me?

Thank you very much!