Mainly plastic, otherwise, I believe the weight penalty will be very significant.
No backlight bleed, at least, I can't see any irregular backlight bleed. But as expected, QLED screen can't display true black like OLED screen, so, it's still very dark grey but not black.
It's hard to capture the black screen in dark by my iPhone 6+. The picture make it looks like some bleeding at the top middle position, but those light are actually the noise of the photo (light reflection from the wall)
This screen is on, and playing pure black video
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This is with the UI to let you know that it's actually playing video but not switched off.
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