The contrast of OLED is between 10x and 100x that of a projector.
When an OLED pixel is off, it reflects ambient light to some degree, but OLED panels are black and have an anti-glare polarizer that dramatically attenuates scattered ambient light. When that same OLED pixel goes on at full brightness, we see the light it emits, plus the small amount of glare from when it was off. Here is the contrast of a display panel:
Intensity when pixel is off = ambient light * panel reflectance
Intensity when pixel is on = Intensity when pixel is off + Intensity from pixel
Contrast = Intensity when pixel is on / Intensity when pixel is off
= 1 + intensity from pixel / (ambient light * panel reflectance)
Because the panel reflectance is very low for OLED displays, this ratio is very large.
With projectors, when a pixel is off, the screen scatters the ambient light. When the pixel turns on, we see the scattered ambient light plus the light from the projector. Here is the contrast calculation for a projector assuming a Lambertian screen (sometimes called a screen with “gain 1.0”):
Intensity when pixel is off = ambient light * screen reflectance
Intensity when pixel is on = Intensity when pixel is off + light from projector * screen reflectance
Contrast = Intensity when pixel is on / Intensity when pixel is off
= 1 + light from projector / ambient light
Unlike OLED panels, the reflectance of the screen has no effect on contrast. A diffuse white screen offers the same contrast as a gray one. In these calculations, I’ve assumed an off pixel emits no light at all. In reality, projectors leak a significant amount of light for off pixels, further impairing contrast.
Inside a typical home, where the ambient light is around 100 lux, the contrast for a projector is around 40:1 citation. In that setting, an OLED display on a phone would exhibit a contrast ratio of 500:1, and a TV’s OLED display would exhibit a contrast ratio of 2000:1 citation.
These observations are inherent to projection. Sadly, improvements in light engines won’t yield better contrast ratios. To get better contrast, one has to do something outside the projector, either on the screen, or near the viewer’s eyes. To get high contrast, Navdy employed a carefully engineered screen. It had a carefully selected curvature, had an aluminized backing, and its surface was covered in microscopic lenses. These features caused it to bounce ambient light away from the viewer’s eye, while reflecting the light from the projector toward the viewer’s eye. This sort of optimization isn’t possible for most projection applications, especially ones that try to make every-day objects feel alive.