In-Cell Vs On-Cell Vs G+G — Touch Integration Structures Explained

In capacitive touch displays, the integration method between the display panel and the touch sensor has a direct impact on optical performance, mechanical reliability, signal stability, repairability, and manufacturing yield.

Among the most common structures used today are G+G (Glass + Glass), On-Cell, and In-Cell.
Although they are often compared mainly by thickness, the real engineering differences go much deeper.

This article summarizes how these three structures differ in construction, performance behavior, and suitable applications.

1. Structural Overview

G+G (Glass + Glass)

• Touch sensor is built as an independent glass panel

• Bonded on top of the display with OCA / LOCA

• Display and touch are two separate functional layers

Typical stack: Cover Glass → Sensor Glass → OCA → Display Panel

On-Cell

• Touch sensor is integrated on the surface of the display panel (usually on the TFT top glass)

• Still a separate sensor layer, but no additional sensor glass

Typical stack: Cover Glass → Sensor Layer (on display) → Display Panel

In-Cell

• Touch sensor electrodes are embedded directly inside the TFT array layer

• Display pixels and touch sensors are manufactured as one integrated structure

Typical stack: Cover Glass → TFT Panel with Embedded Touch Sensor

2. Key Technical Differences

3. Optical and Mechanical Behavior

G+G

• An additional glass and bonding layer increases reflection and parallax

• Highest mechanical rigidity

• Best tolerance to vibration, impact, and temperature cycling

Typical behavior:

• Slightly lower optical transmittance

• Very stable under harsh environments

On-Cell

• Eliminates one glass layer compared to G+G

• Improved transmittance and reduced reflection

• Mechanical strength depends strongly on cover glass design

Typical behavior:

• Balanced optical performance

• Moderate resistance to mechanical stress

In-Cell

• Minimal layer count → highest optical clarity

• Lowest parallax and reflection

• Mechanical strength relies entirely on TFT substrate and cover glass

Typical behavior:

• Excellent visual performance

• More sensitive to bending stress and thermal mismatch

4. Signal Integrity and Noise Sensitivity

G+G

• Long signal routing path

• Higher parasitic capacitance

• Better isolation from display noise

Performance:

• Stable in EMI-heavy or high-noise environments

• Lower risk of display interference

On-Cell

• Shorter routing than G+G

• Moderate coupling with display signals

Performance:

• Good balance between sensitivity and stability

• Requires careful shielding in industrial environments

In-Cell

• Touch electrodes share the TFT environment

• Strong coupling with pixel driving signals

Performance:

• Excellent sensitivity potential

• Higher risk of display noise coupling

• Requires advanced firmware filtering and timing control

5. Manufacturing and Reliability Considerations

G+G

• Mature supply chain

• High yield

• Easy replacement of damaged sensor glass

Advantages:

• Stable cost

• Long-term field reliability

On-Cell

• Yield depends on display vendor capability

• Sensor defects affect the full panel

Advantages:

• Reduced BOM

• Moderate thickness reduction

In-Cell

• Yield highly sensitive to TFT process control

• Sensor defects scrap the full display panel

Challenges:

• Higher manufacturing risk

• More limited supplier base

• More difficult field repair

6. Typical Application Suitability

Best fit for G+G

• Industrial HMIs

• Outdoor terminals

• High-vibration or shock environments

• Long-lifecycle equipment

Best fit for On-Cell

• Embedded panels

• Medical devices

• Semi-industrial terminals

• Balanced thickness vs robustness designs

Best fit for In-Cell

• Handheld industrial devices

• Compact embedded systems

• Weight-sensitive designs

• Consumer–industrial crossover products

Not recommended when:

• Heavy vibration is present

• Extreme temperature cycling is expected

• Long-term repairability is critical

7. Selection Summary

8. Final Notes

Choosing between G+G, On-Cell, and In-Cell should not be driven by thickness alone.
Mechanical stress, EMI environment, repair strategy, lifecycle expectations, and supplier capability are often more critical factors than optical performance.

In industrial and embedded systems, long-term stability usually outweighs minimal thickness.
Understanding these trade-offs early in the design phase helps avoid costly redesigns later.