In industrial HMIs, EV chargers, access control systems, and biometric terminals, engineers selecting projected capacitive touchscreens (PCAP) often face a recurring question besides size, resolution, interface, and brightness:
What kind of surface treatment should we use on the cover glass — AG / AR / AF?
Do we need it at all? Which one? Can we combine several?
This article compares AG (Anti-Glare), AR (Anti-Reflection), and AF (Anti-Fingerprint) from an engineering perspective and provides selection guidelines for typical application scenarios, so you can make faster decisions at project kick-off or sample evaluation stage.
1. Why Do Projected Capacitive Touchscreens Need Surface Treatment?
For B2B devices, touchscreen surface treatments mainly address three types of issues:
- Readability issues
Reflections and glare in strong-light environments make UI content hard to read.
- Contamination and maintenance issues
Fingerprints, oil, dust, and stains affect appearance and hygiene.
- User interaction issues
High sliding friction and inconsistent touch feel reduce HMI efficiency.
AG / AR / AF coatings are applied on the cover glass of the PCAP touchscreen to improve these aspects and enhance overall HMI performance.
2. Key Differences Between AG, AR, and AF Surface Treatments
2.1 AG (Anti-Glare)
Working principle
By etching or coating the glass surface with fine micro-structures, incoming light is scattered, reducing mirror-like reflections and perceived glare.
Engineering characteristics
- Advantages
- Effectively reduces mirror reflections (no more “seeing the lamp or your own face” on the screen)
- Works well in factory lighting, near windows, and semi-outdoor environments
- Trade-offs
- Slight reduction of image sharpness, introducing a “matte / grainy” look
- If the haze level is too high, small fonts and fine lines may appear less crisp
Typical use cases
- Industrial HMIs and machine control panels
- Outdoor / semi-outdoor terminals (EV chargers, agricultural controllers, logistics equipment, etc.)
- Touchscreens paired with high-brightness TFT LCD modules
2.2 AR (Anti-Reflection)
Working principle
A multi-layer optical coating is applied on the glass surface. Through optical interference, it reduces surface reflectance so more light from the TFT module passes through, improving contrast and perceived “clarity”.
Engineering characteristics
- Advantages
- Low reflection while preserving high image sharpness and fine detail
- Suitable where curve plots, graphs, and color accuracy are important
- Trade-offs
- Higher cost than simple AG etching
- More demanding in terms of coating process and cleaning
- Some AR stacks may introduce slight color shift (e.g., a mild bluish or greenish tint), which must be evaluated together with the UI design
Typical use cases
- Medical devices and lab analyzers
- Precision measurement / inspection instruments
- Control rooms and showrooms where both display quality and appearance matter
2.3 AF (Anti-Fingerprint / Easy-Clean)
Working principle
A hydrophobic / oleophobic coating is applied on the surface to reduce fingerprint adhesion, improve sliding feel, and make the glass easier to clean.
Engineering characteristics
- Advantages
- Smoother sliding and touch feel, closer to consumer electronics
- Fingerprints are less visible and easier to wipe off
- Almost no impact on transmission or display resolution
- Trade-offs
- Functional coating with performance that gradually degrades over long-term use
- Requires appropriate cleaning methods (avoid harsh chemicals where possible)
Typical use cases
- High-frequency touch interfaces: smart home panels, industrial operator panels, HMIs
- Applications with higher hygiene and appearance requirements: medical devices, self-service kiosks, etc.
3. Scenario-Based Selection Guidelines
Below are recommendations for AG / AR / AF combinations in common B2B scenarios to help you screen options at design stage.
3.1 Outdoor / Semi-Outdoor HMI and EV Chargers
Typical scenarios
EV charging stations, outdoor energy management terminals, outdoor information terminals, agricultural / construction machinery controllers, etc.
Main pain points
- Direct sunlight or strong reflections make the UI difficult to read
- Fingerprints, water marks, and dust with limited maintenance frequency
Recommended combination
- AG + AF
- AG: controls glare and mirror reflections, improving readability in bright light
- AF: improves sliding feel and makes field maintenance (cleaning) easier
- If budget allows and display performance is critical, evaluate:
- Low-haze AG + AR + AF combinations, validated via A/B comparison on real hardware
3.2 Indoor Industrial Equipment / Machine Control Panels
Typical scenarios
Production line HMIs, PLC operator panels, CNC / machine control terminals, etc.
Main pain points
- Reflection from overhead and side lighting
- Operators may wear gloves or have slightly dirty hands
Recommended combination
- Low-to-medium haze AG + AF
- AG: mitigates reflections and glare from lighting
- AF: keeps the interface cleaner and maintains good touch feel over time
- If the UI contains many graphs, trends, and small-font data:
- Keep AG haze at a moderate level to avoid overly “frosted” screens that make data harder to read
3.3 Medical / Laboratory Equipment
Typical scenarios
Patient monitors, analyzers, diagnostic and lab instruments, etc.
Main pain points
- Accurate reading of waveforms, trends, and fine details
- Regular disinfection and cleaning; chemical compatibility is important
Recommended combination
- AR + AF
- AR: maintains detail and contrast while reducing reflections
- AF: improves cleanability and reduces visible fingerprints
- High-haze AG is generally not recommended here, as it can compromise detail recognition.
3.4 Access Control / Biometric / Time-Attendance Terminals
Typical scenarios
Access control panels, video door phones, time-attendance devices, and face/fingerprint recognition terminals.
Main pain points
- Installed near entrances, with highly variable light conditions
- High touch frequency; fingerprints and smudges are very visible and affect perceived quality
Recommended combination
- AG or AR + AF
- Outdoor or close to bright light sources: prefer AG + AF
- Indoor lobbies and office areas: lean towards AR + AF for a more transparent and premium look
4. Common Misconceptions and Engineering Notes
- "If we use AG / AR / AF, the screen becomes scratch-proof."
- Surface treatments primarily target reflection control, easy cleaning, and touch feel.
- Real scratch resistance mainly depends on cover glass material and tempering / strengthening process.
- "Higher haze AG always means better performance."
- Higher haze brings stronger anti-glare performance but worse perceived resolution.
- For data-heavy HMIs, it is usually better to choose low or medium haze AG and validate with real UI content on prototypes.
- "AF coating means there will be no fingerprints at all."
- AF reduces adhesion and makes fingerprints easier to wipe off; it does not completely prevent fingerprints.
- Proper expectation management with end customers helps avoid misunderstandings around "anti-fingerprint".
- "Surface treatments will harm touch sensitivity."
- With reasonable cover glass thickness and standard AG / AR / AF processes, projected capacitive performance is usually not significantly affected.
- For thick cover glass or glove / wet-hand operation, surface treatments and touch IC tuning should be evaluated together at system level.
5. What Information Should You Share with Your Supplier?
To let your touchscreen supplier propose a suitable AG / AR / AF方案 faster, it is helpful to provide at least the following information:
- Application environment
- Indoor / outdoor / semi-outdoor
- Presence of direct sunlight, strong overhead lighting, window-side installation, etc.
- Display priority
- Requirements for image detail and color accuracy
- Whether there are many trend charts, dashboards, and small-font data
- Operation method
- Bare finger / glove / wet hand
- Touch frequency (occasional vs high-frequency operation)
- Maintenance and cleaning method
- Use of alcohol wipes, specified disinfectants, or daily cleaning procedures
- Required visual performance over the product lifetime
- Cost and lead-time constraints
- Cost ceiling or strict BOM targets
- Whether additional sample rounds for A/B testing are acceptable
The more clearly this information is defined in the requirement document or RFQ, the easier it is for the supplier to converge on an appropriate surface treatment solution and avoid multiple iterations.
6. MAXEN’s Capabilities for PCAP Touchscreen Surface Treatments
In real projects, AG / AR / AF are applied on the cover glass of the projected capacitive touchscreen, working together with the internal TFT LCD module to improve both visual performance and touch experience.
MAXEN can provide, based on project needs:
- AG / AR / AF and their combinations on PCAP cover glass
- Application-driven recommendations for industrial, outdoor, medical, access control, and other scenarios
- Integration with optical bonding to further optimize contrast and reflection performance
- Guidance around touch IC tuning for glove and wet-hand operation, where required
If you are planning a new HMI, EV charger, access control panel or video doorbell and need to evaluate AG / AR / AF options, you can send us your basic requirements (size, brightness, interface, environment and target quantity) via sales@maxen-lcddisplay.com. Sharing these key parameters upfront helps us quickly propose suitable surface treatment options and reduce communication and sampling lead time.
