Surface treatment for Sunlight Readable LCD Displays

Challenges for sunlight readable displays:

As sunlight readable display solutions, you’ve probably tried cranking up the high brightness LCD display or switching to use a transflective lcd display. Is there other way to further improve the displays to more sunlight readability?

The answer is Yes. We could use surface treatment solution for sunlight-readable display. Surface treatment technology is a power saving solution, A LCD display with AG surface treatment + 500 nit brightness, it could be equate to a 800 nits display.

Sunlight readable solutions	Power consumption	Cost	Suitable environment
High brightness display	☆☆☆↑	☆	Indoor & outdoor
transflective tft LCD	☆	☆☆↑	Better for outdoor, but lower brightness indoor
Surface treatment	0	☆~☆☆	Special for strong sunlight directly for outdoor

Therefore, instead of just brute-forcing brightness (and your battery life), you can optimize the display’s surface treatments to make it naturally more sunlight-friendly. No magic tricks—just smart optical engineering.

Here’s what actually works, based on real-world testing and a lot of trials.

1. Impact of Polarizer Haze on sunlight readable lcds.

Definition and Role of Haze: Haze refers to the percentage of light scattering caused by surface or internal microstructures in polarizers. For sunlight-readable LCDs, haze affects:

1. Clarity: Low haze (<3%) minimizes scattering, preserving image sharpness.

2. Anti-glare performance: Higher haze (e.g., 25%) scatters ambient light to reduce reflections but may reduce brightness.

3. Rainbow effect suppression: Moderate haze (5–15%) disrupts interference patterns, mitigating rainbow artifacts from PET substrate birefringence.

4. Haze Impact on Sunlight Readability

Haze Range	Pros	Cons	Best Applications
<3%	High transmittance (≥90%), accurate color	Prone to glare, low contrast in sunlight	High-brightness indoor displays (e.g., medical monitors)
3–10%	Balanced clarity and anti-glare	Requires AR coating for reflection control	Automotive/industrial outdoor HMIs
>10%	Strong anti-glare, rainbow effect suppression	Brightness loss (transmittance ↓15–20%)	Extreme environments (marine, desert)

Key Selection Criteria for polarizer’s haze of sunlight readable displays:

1. Transmittance vs. Haze Trade-off

• High brightness needed: Low haze (1–3%) + high-transmittance polarizers
• Anti-glare priority: AG-treated polarizers (haze 10–25%), such as matte TAC films.

2. Material Compatibility

• TAC substrate: Precise haze control (0.2–0.3%), ideal for high-resolution displays.
• PET substrate: Avoid haze >5% to prevent birefringence issues.

3. Environmental Testing

• UV aging: Ensure haze stability (e.g., choose adhesive materials prevents yellowing).
• Temperature cycling: Haze variation should be <5% under 85°C/85% RH (industrial-grade requirement).

2.  Polarizer selection about linear polarizers or Circular polarizers for sunlight readable LCD displays.

Linear Polarizers: Only allow light vibrating in one direction (e.g., vertical or horizontal) to pass through. Block all other light orientations.

Circular Polarizers: First polarize light linearly, then pass it through a quarter-wave plate to convert it into circularly polarized light (left- or right-handed).

Most LCDs use linear polarizers, which are cheap and widely available. But under direct sunlight, they struggle with:

-- Glare from metallic surfaces (like car dashboards or industrial equipment)

-- Light leakage, reducing contrast

2.1 What Kind of Polarizer We Should Use for sunlight readable displays:

1.  High-efficiency polarizers (≥99%)

Brands like Nitto’s NPF series cut light loss dramatically.

Yes, they cost 15–20% more, but the contrast boost is worth it.

2.  Circular polarizers (if reflections affact you so much)

Ever noticed how your phone screen looks terrible with polarized sunglasses? That’s linear polarization at work.

2.2 Circular polarizers fix this—perfect for automotive and outdoor kiosks.

Circular polarizers solve glare from metal surfaces (e.g., machinery, tool reflections). The theories are:

1. Light Polarization Twist

-- Linear polarizers (used in most LCDs) only block light vibrating in one direction.

-- When this polarized light reflects off metallic surfaces, it often rotates, creating blinding glare.

2. Circular Polarizers Add a Phase Shift

-- They use a quarter-wave film to convert linearly polarized light into circularly polarized light.

-- After reflecting off metal, the light’s polarization direction reverses (e.g., left-handed → right-handed).

3. The Final Block

-- The reflected light can’t pass back through the circular polarizer, killing glare.

The theory of circular polarizer used for sunlight readable LCD for reducing refraction:

Unlike linear polarizers, they work even at oblique angles (critical for tilted panels). Machines often have shiny metal housings—circular polarizers prevent "whiteout" reflections.

Disadvantage for circular polarizers is the cost, it is 10–15% pricier than linear ones.

Therefore:

-- If reflections aren’t a big issue, high-efficiency linear polarizers would be a better soluton.

-- If you’re dealing with metal surfaces environments, go circular.

3. Cover Glass treatment for Sunlight readable tft touch screen: Anti-Glare and Anti-Reflective

3.1  Anti-Glare (AG) Glass: The Classic Fix

AG glass has a lightly etched surface that scatters light, reducing glare. AG glass has surface microstructure scattering: By chemically etching or spraying to form a micrometer-level rough structure (Ra 0.2—5μm) on the glass surface, incident light undergoes diffuse reflection, reducing specular reflection.

Haze control: Generally, the haze of AG glass is between 5% and 25%. The higher the haze, the stronger the anti-glare effect, but it may reduce the light transmittance.

Advantage:

• Works well in bright, diffuse lighting (like cloudy days).
• Cheaper than AR coatings—good for budget projects.

Disadvantage:

• Slightly blurs fine details (bad for high resolution displays).
• Can look "sparkly" under certain angles.

Best for:

• Industrial HMI displays, outdoor payment terminals.

3.2  Anti-Reflective (AR) Coatings: The Premium Option

AR coatings use microscopic layers (like SiO₂/TiO₂, 4 to 7 layers) on the glass surface to eliminate reflection through light interference (principle similar to camera lens coating). It is low haze (<1%) value, that almost no effect on light transmission and clarity.

Advantage:

• Near-invisible reflections (if done right).
• Doesn’t blur the image like AG.

Disadvantage:

• Expensive (multi-layer coatings can double the glass cost).
• Scratches easier than AG—needs a protective top layer.

Best for:

• High-end displays (medical, military, automotive).

Suggestion from Maclight:

• If you need sharpness and clarity, AR surface treatment would be better.
• If you’re on a tight budget, AG surface treatment is still a solid choice.

4. Future technologies for Sunlight Readable Display

Micro-LED + Surface Treatments = The Ultimate Combo

Micro-LEDs are inherently sunlight-friendly, but pairing them with AR coatings and OCA bonding makes them unbeatable.

Self-Cleaning Coatings (For Displays That Stay Clean)

Some nano-coatings (like TiO₂) break down dirt under UV light. Great for public kiosks that get grimy.

Electrochromic Dimming (Like Mercedes’ Hyperscreen)

Displays that automatically tint in bright light? Yes, it’s a thing—but still expensive.

5. Final Recommendations

1. Start with the right polarizer (high-efficiency or circular, and haze value).
2. Pick AG or AR glass based on budget and clarity needs.

If You Need help sourcing sunlight readable LCD displays? Please contact Maclight display for further helps: email: [email protected]