Capacitive Touch Panel (CTP) Technology Introduction

The abbreviation for Capacitive Touch Panel is CTP or PCAP.

Before we start to introduce Capacitive Touch Panel (CTP) Technology, we are compelling to have two break ground stories to tell. Both related with Steven Jobs.

  • iPhone and iPad

It’s no secret that Steve Jobs had a huge impact on the world of technology, but perhaps his legacy will be felt most significantly in mobile. No matter the smartphone, it works the way it does now because back in 2007 Steve Jobs stood on a stage before a throng of reporters and said, “Who wants a stylus? … Yuck!”. Apple was not the first company to look at capacitive touch technology, but it was the first to make it really work on a phone.

Indeed, Steve Jobs almost missed out capacitive touch technology on the iPhone and iPad altogether. That’s because he didn’t see “any value to the idea” of multi-touch: the breakthrough touchscreen technology which makes iOS regulars like “pinch-to-zoom” possible.

And it was left up to Ive and a few other core Apple employees to save it. Multi-touch at Apple began with a demo from Greg Christie and Bas Ording, who spent several months in 2004 creating a working prototype of an iPad-like screen, the size of a conference table. On it, a person could use two hands to move folders around, activate icons, shrink and enlarge documents, and “scroll” vertically and horizontally using swipes. They presented the tech to top Apple executives by projecting it onto a video screen.  Jobs had been excited about creating a tablet, but he was less than impressed by the demo.

After thinking about the idea for a few days, however, Jobs came around — and ran it past a number of Apple executives whose opinions he trusted. Jobs wasn’t immediately convinced he could make a go of a tablet as a mass-market product, but as a phone he could certainly see the application. He told Tony Fadell to “go figure out how to add this multi-touch interface to the screen of a phone. A really cool, really small, really thin phone.”

The rest, as they say, is history.

  • Gorilla Glass

About six months before the iPhone hit store shelves in 2007, Steve Jobs called Corning’s CEO, Wendell Weeks, and asked him if he could create a glass cover for a new Apple product that would resist scratches and breakage.

Actually, the original iPhone spec called for a plastic cover over the touchscreen display. The story goes that Jobs, after using a prototype iPhone for a few weeks, became very worried that the device’s display would get scratched when jumbled around in user’s pockets with keys and coins. So he gathered his engineers and demanded a new glass covering be used for the iPhone. Hence Jobs’ phone call to Weeks.

Jobs’ six-month deadline was a real challenge for Corning, it normally takes Corning close to two years of R&D to get any new product to market. Fortunately, like the iPhone itself, Gorilla Glass benefited from some earlier R&D. In the 1960s Corning had worked on strengthened glass for car windshields, and while that product never came to market,

With a call from Steve Jobs, a legend was born.

Steve Jobs didn’t invent capacitive touchscreens, nor did the Apple engineers. The first prototypes showed up in the 1960s. The iPhone wasn’t even the first application of the multitouch technology. Steve Jobs and Apple engineers simply made capacitive touchscreens irresistible.

  • Touch Panel Classification

Orient Display: Touch Panel Classification

  • RTP (Resistive Touch Panel) vs CTP (Capacitive Touch Panel)

Orient Display: RTP (Resistive Touch Panel) vs CTP (Capacitive Touch Panel)

  • Capacitive Touch Panel (CTP) Classification – Principle Types

Orient Display: Capacitive Touch Panel (CTP) Classification- Principle Types

    • Self-Capacitance

      • Detect the capacitance between sensor and ground;
      • Driving and sensing at the same sensor.


Fig. 1 Self-capacitance


    • Mutual Capacitance

      • Detect the capacitance between drive sensor and receive sensor;
      • Drive sensor generates pulse signal, then receive sensor detects.


Orient Display: Mutual Capacitance

Fig. 2 Mutual Capacitance

Self-Capacitance PROs

      • Simple control circuit
      • Low cost

Self-Capacitance CONs

      • Single-Touch + Gesture
      • Low SNR (signal noise rate)

Mutual Capacitance PROs

      • True Multi-Touch (Up to 16)
      • High SNR (signal noise rate)

Mutual Capacitance CONs

      • Complex control circuit
      • High cost


  • Capacitive Touch Panel (CTP) Classification – Function Types


    • Key or Button Type Touch

Orient Display: Key or Button Type Touch

Fig. 3 Key or Button Type Touch


    • Single Touch or Two Finger Touch or with Gesture

Orient Display: Single Touch

Fig. 4 Single Touch

Orient Display: Two Finger Touch or with Gesture

Fig. 5 Two Finger Touch or with Gesture


    • Multi-Touch

Orient Display: Multi-Touch

Fig. 6 Multi-Touch


  • Capacitive Touch Panel (CTP) Classification – Structure Types

Orient Display: Capacitive Touch Panel (CTP) Classification- Structure Types

Orient Display: On-Cell and In-Cell Touch Structure

Fig. 7 On-Cell and In-Cell Touch Structure


Orient Display: Glass and Film type Capacitive Touch Panel Structure

Fig. 8 Glass and Film type Capacitive Touch Panel Structure


  • Comparison of Different Capacitive Touch Panel Structures


  • Cover Lens Material Choices


Glass cover lens impact resistance


  • CTP Surface Treatment

Orient Display: CTP Surface Treatment

Fig. 9 CTP Surface Treatment


  • Anti-Shattering Treatment (ASF)

Orient Display: Anti-Shattering (ASF)

Fig. 10 Anti-Shattering (ASF)


  • Anti-Fingerprint (AF) Coating

Orient Display: Anti-Fingerprint Coating

Fig. 11 Anti-Fingerprint Coating


    • Excellent water and oil repellency for glass surface;
    • Ultra slippery, improve touch screen operability.


  • Anti-glare (AG) Treatment

Orient Display: Anti-glare (AG) Treatment

Fig. 12 Anti-glare (AG) Treatment



    • The anti-glare can be made either on glass (7H) or film (3H);
    • We can make less sparking on displays, supporting 200 ppi high definition.


  • Anti-reflective (AR) Treatment

Orient Display: Anti-reflective (AR) Coating

Fig. 13 Anti-reflective (AR) Coating


Orient Display has other technologies to make the performance better.

  • Index Match ITO (IM) Technology

Orient Display: Index Matching (IM) Coating

Fig. 14 Index Matching (IM) Coating



    • Control the reflectance from 400-700nm;
    • Reflectance less to 1.5% for CTP only, and 3% for optical bonding units, and 7% for air bonding units;
    • Good for ITO traces and metal bridges;
    • Special inner IMITO treatment makes ITO invisible.


  • Optical Bonding (Full Lamination)

Orient Display: Optical Bonding vs Air (Perimeter) Bonding

Fig. 14 Optical Bonding vs Air (Perimeter) Bonding



    • Orient Display can do either OCA (dry) or OCR/OCG (Wet) bonding;
    • OCA can go up to 15” and OCR can go up to 32” in Orient Display;
    • Orient Display can do automotive or outdoor grade optical bonding.

Orient Display: Air Bonding vs Full Lamination


  • Touch with Different Touch Materials

Orient Display: Capacitive Touch Panel with Pencil, Rubber, Glove and Stylus

Fig. 16 Capacitive Touch Panel with Pencil, Rubber, Glove and Stylus


    • Automatically recognize passive pen/glove/finger;
    • Support minimum diameter of passive pen: 2mm;
    • Support up to 5mm thickness gloves.


  • Touch with Different Glove Materials

Orient Display: Touch with Different Glove Materials

Fig. 17 Touch with Different Glove Materials


    • Support different materials: Cotton, leather, wool, latex etc.;
    • Maximum thickness can be up to 5mm.


  • Touch with Water and Salt Water

Orient Display: Touch with Water and Salt Water

Fig. 18 Touch with Water and Salt Water


    • No hop with salt water spraying;
    • Normal single touch;
    • Normal two fingers touch
    • Up to 5% salt water


  • Hover Touch

Orient Display: Hover Touch

Fig. 19 Hover Touch


    • Self-mutual capacitive touch technology;
    • Up to 20mm hover operation;
    • Up to 100mm proximate function;
    • Support single touch only


  • Force (3D) Touch

Orient Display: Force (3D) Touch

Fig. 20 Force (3D) Touch


  • Haptic touch

Orient Display: Haptic Touch

Fig. 21 Haptic Touch


Haptic Touch technology is similar to Force or 3D Touch but it doesn’t rely on pressure. Instead, Haptic Touch kicks in when a user long-presses the screen, offering a small vibration as acknowledgment following the press – haptic feedback as it is officially known, hence the Haptic Touch name.