Projected Capacitive (PCAP) and Surface Capacitive are distinct touchscreen technologies differing in structure, sensing methods, and applications. Surface Capacitive uses a single conductive ITO layer to detect touch via field distortion, supporting single-point interaction. Projected Capacitive employs multilayer ITO electrode matrices for precise multi-touch detection, enabling simultaneous contact tracking and higher sensitivity without direct pressure.
What Is Tandem OLED and Why Is It Important?
How do sensing mechanisms differ between the two technologies?
Surface Capacitive relies on electric field distortion from touch, measuring current variation at screen corners. Projected Capacitive detects mutual capacitance shifts between intersecting X/Y electrodes, enabling pixel-level tracking.
While Surface Capacitive calculates coordinates through analog voltage ratios across its conductive layer, PCAP uses digital scanning to measure capacitance changes at each electrode intersection. For example, iPhone’s PCAP sensors scan 300+ times/sec to detect 10 simultaneous touches with 1mm accuracy. Pro Tip: PCAP’s matrix structure enables glove compatibility through adjustable sensitivity thresholds—Surface Capacitive requires bare skin contact.
| Feature | Surface Capacitive | Projected Capacitive |
|---|---|---|
| Sensing Method | Field distortion | Matrix coupling |
| Multi-Touch | Single-point | 10+ points |
| Input Type | Finger/stylus | Finger/glove/conductive tools |
What structural variations define these technologies?
Surface Capacitive uses single-layer ITO coated glass, while PCAP deploys X/Y electrode grids laminated under cover glass, enabling z-axis proximity detection.
Surface Capacitive screens consist of a uniform ITO layer (≈150Ω/sq) with corner electrodes. PCAP stacks two patterned ITO layers (50-100nm thickness) separated by dielectric—one with horizontal rows, the other vertical columns. The overlapping intersections create 5-15pF capacitors. Practical example: ATMs use Surface Capacitive for vandal resistance, whereas modern POS terminals adopt PCAP for signature capture. Pro Tip: PCAP’s layered design achieves ≤88% optical transparency versus Surface Capacitive’s 90%, but compensates with zero-pressure activation.
Panox Display Expert Insight
FAQs
PCAP excels with glove-compatible moisture rejection. Surface Capacitive suffers false triggers from water droplets due to broad field sensitivity.
Can Surface Capacitive support 4K displays?
Yes, but limited to 20mm electrode pitch. PCAP enables ≤5mm pitch for ultra-high-resolution panels through photolithography-patterned ITO.