I did some research on OLED panel manufacturing over the weekend, and there are some interesting differences between how Samsung Display and LG Display build their iPhone panels. The TL;DR is that:
All iPhone OLEDs are cut from large mother glass sheets (typically Gen 6, about 1.5 × 1.85 m) on which dozens of panels are deposited at once. Slight temperature and deposition-rate differences across that sheet make center-cut panels slightly more uniform than edge-cut ones (see Jeon et al., J. SID 24 (8), 2016). Apple doesn’t “bin” screens by supplier or storage tier — every panel that meets its ΔE < 2 white-point spec is calibrated and installed on the same production line (DisplayMate, 2023 iPhone 14 Pro Report).
Samsung and LG both use RGBG (Pentile) OLED structures, but their optical stack tuning differs. Samsung’s M-series panels employ a narrow, tightly tuned microcavity and a multi-layer birefringence compensation stack (Lee et al., SID 2019) that slightly over-corrects red + blue to suppress the usual green-cyan shift, which can make whites take on a faint pinkish hue at wide angles. LG’s C-series panels use a broader resonance cavity and thinner compensation films (WO 2019/200935 A1, LG Display) that favor higher luminance and warmer on-axis whites but allow a mild green/cyan shift off-axis as red light falls off faster.
Both designs are trade-offs, not quality tiers. Apple calibrates every panel’s white balance, gamma, and uniformity in firmware and adds True Tone compensation on top, so day-to-day color differences are within measurement noise. The remaining variance — cooler vs. warmer whites, slight pink or green tint at an angle — comes from variations in manufacturing physics and the fact that the human eye is most sensitive to green luminance (Fairchild & Wyble, Color Res. Appl., 2010). Every iPhone display is meant to be built to the same standard, but each carries its own microscopic optical “fingerprint” — the panel lottery is real, just not a matter of better or worse.
I have pages and pages of notes on this, if y'all want to take a deeper dive, just let me know.