Types of Privacy Films
| Type | Principle | Features | Typical Applications |
| Micro-Louver Type | Uses micro-louver structures to restrict the light emission angle (e.g., ±30° or ±45°) | Mainstream type; clear front view, darkens when viewed from the side | Smartphones, laptops, ATMs, car displays, industrial monitors |
| Polarization Type | Uses a polarizer to restrict the light vibration direction | Higher cost, slightly lower transmittance; suitable for high-contrast displays | High-end industrial displays, medical devices |
| Diffusion Type | Scatters light with micro-particles to reduce side visibility | Low cost, modest privacy effect, significant brightness reduction | Price-sensitive products |
| Hybrid Type | Combines micro-louver with polarizer or anti-reflection | Offers multiple functions: privacy, anti-glare, anti-fingerprint | High-end laptops, tablets, car infotainment screens |
Currently, we mainly use micro-louver type privacy films. The following structure diagrams illustrate the principle:
The micro-louver layer resembles tiny blinds (spacing only tens of microns) that allow light to pass in a specific direction (vertical or ±30°).
- Front view: Light passes directly → screen content is clear
- Side view: Light blocked by louvers → screen darkens or becomes invisible
Typical privacy angles:
- Horizontal: 30°, 45°, 60°
- Vertical: Up/down privacy is also possible (used for laptops, ATMs, etc.)
From the third structural diagram (this is an automotive light-controlled privacy film), we can see that there are AG layers on both the top and bottom of the privacy film. This type of structure is commonly referred to as a Double-sided AG Privacy Film.
Features:
- Double-sided anti-glare (AG): Reduces reflections on both surfaces, improves display visibility, scratch-resistant
- Privacy protection: Darkens at side angles to prevent viewing by others
- Surface feel: Fine matte AG texture, good anti-fingerprint performance
- Applications: Outdoor high-brightness TFT LCDs, car displays, industrial monitors, laptops
Structure of Privacy Film
Privacy films are multi-layer composites. Key layers include the base layer, micro-louver layer, OCA, plus optional layers like hard coating and adhesive layers.
- Hard Coating Layer: Scratch-resistant, increases surface hardness (typically 3H–9H)
- Base PET Layer: Provides mechanical strength and stability
- Micro-Louver Layer: Core privacy structure controlling light direction
- Optical Adhesive (OCA): Bonds layers while maintaining optical clarity
- Adhesive/Silicone Layer: Allows attachment to the screen surface, can be removed and reapplied without residue
Installation Methods
- Surface-mounted: Uses silicone or OCA; easy to apply, removable; reduces surface hardness
- Embedded: Laminated inside the LCD module; higher protection, does not affect surface hardness
- Magnetic/Clip-on: External, detachable; often used for monitors
In our industry, the simplest approach is to attach the privacy film directly to the display surface:
- Pros: easy, low cost
- Cons: reduces surface hardness
Another method is to insert the film between the backlight and LCD glass: - Pros: preserves surface hardness
- Cons: adds to assembly complexity
Key Parameters of Privacy Film
Privacy film parameters fall into four categories: optical, physical structure, environmental/ durability, and surface functions.
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Optical Parameters:
- Visible Light Transmittance (VLT): Ratio of visible light passing through; higher value → brighter screen.
- Typical range: 50%–85%
- Viewing Angle / Privacy Angle: Screen is clear at center, darkens beyond this angle.
- Typical range: ±30°, ±45°, ±60°
- Haze: Degree of light scattering; higher haze reduces glare but slightly lowers clarity.
- Typical range: 2%–15% (AG surface)
- Reflectance: Surface reflection rate; affects anti-glare performance.
- Typical range: 1%–10%
- Polarizer Compatibility: Must match TFT LCD polarizer to avoid distortion or color shift
- Typical range: To Be Verified by Testing
Optical parameters are our main focus. The following are the specifications for the double-sided anti-glare privacy film:
- Total Light Transmittance: ~70%–80% (high-transmittance privacy film); e.g., a 1000 nits display may drop to 700 nits
- Transmittance: 70%–80% indicates a high-transmittance privacy film.
- Haze: 10%–40% clearly shows that the surface has been treated with AG (anti-glare) coating.
- Up/down (Vertical Viewing Angle) 30° transmittance ≤15%:
- Up/down 30° angle (±30°): Refers to the viewing angle 30° above or below the vertical center of the screen (vertical privacy direction).
At this angle, visible light passing through the privacy film is less than 15% of the front brightness.
This indicates that the film provides vertical (up/down) privacy protection.
- Transmittance <15%: At this angle, the intensity of visible light passing through the privacy film is less than 15% of the front-facing brightness.
This means that the privacy film provides vertical (up/down) privacy protection.
| Item | Unit | Typical Value | Testing Standard |
| Thickness of Functional Layers | µm | 370±20 | GB/T 33399 |
| Total Light Transmittance | % | ≥70 | GB/T 2410 |
| Haze | º | 10~40 | GB/T 2410 |
| Transmittance at 30°
Vertical Viewing Angle |
% | ≤15 | / |
PS: The table below shows the characteristics of privacy films with different Transmittance levels. This is also helpful for our selection process.
| Type | Transmittance (Approx. Range) | Features |
| Standard HD Film | 90%–95% | Clear display, minimal brightness loss |
| Privacy Film (Standard) | 50%–70% | Noticeable viewing angle limitation, screen slightly darkened |
| High-Transmittance Privacy Film | 70%–80% | Maintains privacy while minimizing brightness loss |
| Strong Privacy Film | 40%–55% | Strong privacy effect, but darker screen and deeper colors |
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Physical / Mechanical Parameters
- Total Thickness: Overall thickness including PET substrate, AG layer, privacy layer, etc.
Typical range: 0.1–0.5 mm - Base Material: PET, PC, PMMA, Glass Composite, etc.
Typical range: Depends on application - Surface Hardness: Scratch resistance, usually expressed in pencil hardness (H)
Typical range: 3H–9H - AG Layer Roughness (Ra): Affects haze, feel, and anti-reflection performance
Typical range: 0.02–0.1μm - Adhesive Type: Silicone, OCA, or adhesive-free electrostatic
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Durability / Environmental Tests
- Operating / Storage Temperature Range: Typically -20℃ to +80℃
- Humidity Resistance: No bubbling or discoloration after 60℃ / 90% RH test
- UV Resistance: No yellowing after prolonged exposure
- Adhesion Strength: Strength of adhesive bonding to the screen
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Surface Treatments / Functionalities
- Anti-Glare (AG): Reduces reflection, improves outdoor readability
- Anti-Fingerprint (AF): Oleophobic/hydrophobic, easy to clean
- Anti-Scratch: Enhances wear resistance
- Anti-Reflection (AR): Improves optical contrast
- Anti-Static: Prevents dust attraction
The table below shows how to evaluate or select different types of privacy films based on their parameters.
| Dimension | Micro-Louver | Polarization | Diffusion | Hybrid |
| Viewing Angle | Clearly specified ±30° / ±45° | Smooth decay curve | Not specified, only “blurred” | Both ± angles + polarizer transmittance data |
| Transmittance (Tt) | 60–75% (relatively high) | 35–50% | 50–70%, haze > 60% | 40–60% (depends on structure) |
| Haze | 10–25% | 20–40% | 60–90% | 30–60% |
| Contrast Retention | ≥90% (front view) | ~80% | <70% | 70–90% |
| Thickness / Layers | 0.25–0.4 mm, double or triple layer | ~0.2 mm, with polarizer | <0.2 mm, single or double layer | >0.4 mm, multi-layer stack |
| Microstructure Feature | Visible parallel micro-groove array | No micro-grooves, anisotropic film | Rough matte | Micro-grooves + polarizer layers |
Should you have any questions about privacy film, please consult our engineering.