Privacy Smart Glass Buyers Guide and Cheat Sheet

Choose the Right Privacy Glass Quickly

We get it.

You don’t have much time to investigate this topic.

You just received a customer request to install some privacy glass and you are not sure what is available on the market.

Should you go for smart (switchable) technologies? If so, which ones are best suited for your project?

Unsurprisingly, this decision depends on the following factors:

• what purpose the privacy glass serves;
• what it is protecting;
• where it will be deployed.

So, let us help you choose which technologies to procure for your project.

Ask These Questions to Select the Optimum Privacy Glass

We have been designing, building and delivering smart glass solutions since 2009 so we have refined our customer-facing techniques in ways that will help you now.

Here are six questions you should ask your customer (or ask yourself if you are building the solution in-house).

Q1. Do you need to see clearly what is behind the glass?

‘Seeing clearly’ implies a requirement to read text, to visualise details or colors, or to ensure that everyone can view what is behind the glass (including vision-impaired people).

Applications:

• Retail displays, partitions or storefronts
• Office documents in legal / financial services
• Patient (or data) privacy in healthcare
• Industrial applications requiring security

What to look for:

Avoid technologies with a polymer matrix, as this increases haze, reducing visibility and readability. Also aim for maximum visible light transmittance (VLT) to ensure that users can view in photopic visibility (i.e. daytime vision).

Recommended:

• Dyed Liquid Crystal (DLC)

Tints by absorbing light, rather than scattering it; offers haze of around 2-3%. If the ambient light levels are low, this can control visibility on-demand.

• Suspended Particle Devices (SPD)

Tints by absorbing light; best for enclosed displays where the interior is dark. Colour rendering is excellent (around 95). Haze around 2-3%.

Avoid:

• Polymer-Dispersed Liquid Crystal (PDLC)

Scatters light. Slightly higher haze in its minimum state, e.g. 3% to 6%.

• Dyed PDLC (D-PDLC)

Same as PDLC but with embedded dyes, which is useful for reducing heat gain (SHGC) and visible light transmittance (VLT) in building facades, but haze is around 3% to 6%.

• Dye-Doped PDLC (DD-PDLC)

This hybrid technology dissolves dichroic dyes into PDLC; transitions from a dark, translucent state to a darkish transparent state, achieving some degree of privacy and solar shading. Not ideal for clear, readable situations though.

Q2. Does the glass need to switch quickly?

The requirement ‘quickly’ is rather vague, but we use the same user experience as for an iPhone when you swipe to accept an incoming phone call. 

If it takes more than 2-3 seconds to respond, most people would consider this ‘too long’. So, if your customer replies positively to this question, we recommend the following.

Applications:

• Retail displays, partitions or storefronts
• Office documents in legal / financial services
• Patient (or data) privacy in healthcare
• Industrial applications requiring security

What to look for:

Must respond as quickly as a typical consumer device (such as an iPhone or iPad).

Recommended:

These technologies activate in 1-3 seconds:

• Polymer-Dispersed Liquid Crystal (PDLC)
• Dyed PDLC (D-PDLC)
• Dye-Doped PDLC (DD-PDLC)
• Dyed Liquid Crystal (DLC)
• Suspended Particle Devices (SPD)
• Electrophoretic (EP)

Avoid:

• Electrochromic smart glass

Typically switching times in the order of 30 seconds to 30 minutes. Great for building facades; not so great for quick conceal / reveal situations.

• Thermotropic smart glass

Scatters light when triggered by heat. Both thermochromic and thermotropic materials take in the order of minutes to fully change state.

Q3. Will the privacy glass be installed in wet or hazardous areas?

The problem here is not the glass. Privacy glass is laminated and thus entirely safe.

The problem is the cable that exits the glass and how that cable is treated.

If the cable can be bent, cut, gnawed by animals or damaged by movement, this may break the cable sheath, exposing the conductors and increasing the risk of a short circuit or electrical fire.

Use our parameterised search to identify technologies with a specific Operating Voltage, by setting the parameter to a value that allows safe installation according to international law (or your national law).

Here are the technologies we would recommend in this case.

Applications:

• Swimming pools
• Bathrooms & kitchens
• Industrial processes with reactive or flammable gasses

What to look for:

Choose a low-voltage technology

Recommended:

Low-voltage, low-current technologies include:

• Electrophoretic (EP) smart glass
• Electrochromic (EC) smart glass

The degree of privacy will depend on the ambient lighting conditions.

If these are very low, the dark state in both these technologies may obscure the view sufficiently, effectively hiding what is behind the privacy glass.

Avoid:

If possible, avoid mains-connected technologies, even if connected by an isolating safety transformer. Prefer battery-operated for extreme safety environments.

Technologies to avoid for high-risk environments include:

• Polymer-Dispersed Liquid Crystal (PDLC)
• Dyed PDLC (D-PDLC)
• Dye-Doped PDLC (DD-PDLC)
• Dyed Liquid Crystal (DLC)
• Suspended Particle Devices (SPD)

Additional Notes:

At the risk of repeating ourselves: the glass itself is laminated and safe. The risk is in how the cables are routed and managed over time.

Q4. Do you need to control the glass electronically?

This requirement should be pretty self-evident, and implies on-demand user control over the level of privacy afforded by the glass. 

If this is indeed a requirement, we recommend the following.

Applications:

• Retail displays, partitions or storefronts
• Office documents in legal / financial services
• Patient (or data) privacy in healthcare
• Industrial applications requiring security

What to look for:

Electronic control via manual switches, remote controllers, sensor-driven activation, or building management systems.

Recommended:

• Polymer-Dispersed Liquid Crystal (PDLC)
• Dyed PDLC (D-PDLC)
• Dye-Doped PDLC (DD-PDLC)
• Dyed Liquid Crystal (DLC)
• Suspended Particle Devices (SPD)
• Electrophoretic (EP) smart glass
• Electrochromic (EC) smart glass

Avoid:

• Thermochromic / Thermotropic smart glass, as they are both triggered by heat
• Photochromic glass, as it is triggered by light / UV

Q5. Do you want to obscure only the data?

If you want to obscure the data present on an electronic screen, there is only one technology we can recommend.

Applications:

• Office documents in legal / financial services
• Patient (or data) privacy in healthcare
• Industrial applications requiring security

What to look for:

Data obfuscation technology.

Recommended:

There is only one suitable technology in this case:

• Data Cloaking Film or Glass

This technology works by selectively blocking specific frequencies emitted by digital displays, while keeping the surrounding glass transparent.

Also great for daylighting in board rooms and meeting rooms with glass walls. Available as a retrofit film.

Q6. Must the glass default to transparent when the power goes off?

Applications:

• Fire doors
• Safety requirements in transportation, defence, industrial

What to look for:

If the power supply is compromised, and you need to see what is on the other side of the window, door, skylight, or partition.

Recommended:

Only one choice here:

• Polymer Network Liquid Crystal (PNLC)

also called ‘Reverse PDLC’, this technology is transparent in the unpowered state; and translucent (scatters light) when powered.

You can search for this category on our Supplier Search page.

How Different Privacy Glass Technologies Work

Here is a quick tutorial on privacy glass technologies, and why some are suited for specific situations over others.

What is privacy glass?

Privacy glass reduces visibility on what is behind it.

Some are static (they have only one ‘optical state’), whereas others are smart / dynamic / switchable and can change their level of visibility between multiple optical states.

Most people associate this requirement with light-scattering technologies, such as liquid crystal based glass, but any glass which tints strongly (by absorbing light) could also achieve the same goal.

Examples of ‘smart’ privacy technologies include those mentioned above:

• Polymer-Dispersed Liquid Crystal (PDLC)
• Dyed PDLC (D-PDLC)
• Dye-Doped PDLC (DD-PDLC)
• Dyed Liquid Crystal (DLC) (no polymer)
• Polymer Network Liquid Crystal (PNLC) or ‘Reverse PDLC’
• Suspended Particle Devices (SPD)
• Electrophoretic (EP) smart glass
• Electrochromic (EC) smart glass
• Thermotropic (TT) smart glass
• Data Cloaking Film or Glass

What applications are best served by smart privacy glass?

The privacy afforded can achieve the following benefits:

• Improve user comfort and the perceived ‘feeling of safety’ or ‘feeling vulnerable’ (e.g. healthcare)
• Reduce regulatory compliance issues due to data theft (e.g. financial institutions)
• Reduce security risks and terrorist threats (e.g. nuclear energy plants, manufacturing plants, data centres)
• Empower exclusivity and targeted sales strategies (e.g. luxury retail)

Why are so many switchable privacy glass technologies based on liquid crystals?

Liquid crystals are free-flowing liquids with a crystalline structure that can change their orientation when under the influence of an applied electric field.

You can read more about them in our tutorial article.

• When liquid crystals are unpowered, they sit in a random orientation and scatter the passage of light (they appear translucent, hiding whatever sits behind the privacy glass). 
• When we apply a voltage to them, they point ‘in the same direction’ as the electric field, allowing light through (i.e. they appear transparent, revealing what is behind the glass).

Hence, privacy glass, whether traditional or ‘smart’ is often associated with light-scattering technologies.

A simple wrist watch from the 1970s uses this same technology. Only recently has this same principle been applied to other applications of glass, such as windows in buildings, vehicles and consumer appliances.

What happens if there is a power outage? 

Most privacy glass will turn opaque or translucent if the power is lost. 

If transparency during an outage is a safety requirement (for example, in fire doors or escape routes), you should specify “Reverse PDLC” (PNLC) technology, which is transparent when unpowered and becomes translucent when we power it.

What is the difference between Dyed PDLC (D-PDLC) and Dye-Doped PDLC (DD-PDLC)?

The difference is where the dye molecules reside and how they interact with light:

Dyed PDLC (D-PDLC):

Dye molecules are randomly dispersed in both the polymer and the liquid crystals. The polymer-trapped dye cannot align with the electric field and relies on color filtering combined with scattering.

Result:

• Lower contrast ratio
• Reduced transparency
• Weaker color saturation

Dye-Doped PDLC (DD-PDLC):

This technology is based on ‘guest-host’ chemistry, with dissolved dichroic or fluorescent dyes embedded inside the liquid crystal droplets. The dyes reorient themselves alongside the LC molecules when we apply an electric field and mimic the liquid crystals, changing color intensity based on their orientation.

Result:

• Higher contrast ratio
• Excellent transparency
• Deep, strong color saturation

Can dynamic privacy glass be installed on curved surfaces? 

Yes, absolutely. Advanced manufacturing allows for switchable smart glass to be curved. 

This is a popular option for modern architectural designs where you want to remove intrusive corners and maximize daylighting while retaining the ability to toggle privacy.

How do I clean and maintain privacy glass? 

Privacy glass is very low maintenance, as it eliminates the need for dusty, unhygienic blinds or curtains. 

You can clean the surface just like standard glass using a soft, non-abrasive cloth and standard glass cleaner. Avoid harsh solvents though, and ensure no moisture enters the frame or electrical connection points.

Wrapping Up

Privacy smart glass is a versatile technology that improves security, enhances exclusivity and delivers user comfort by concealing people, objects or data on-demand. 

Choosing the most suitable technology for your project depends on your specific needs:

• Visibility & Speed
• User Control
• Data Security
• Safety & Risk Mitigation

Using this cheat sheet, you can select the ideal privacy solution for your project quickly, avoiding expensive mistakes.

Next Steps 

If you are ready to look for privacy glass suppliers, use our parameterised search to zoom in on privacy products by objectives and product attributes, such as haze, power consumption and VLT.

This is much faster than trawling through datasheets surfaced by Google, and does not suffer from AI hallucinations, since we verify all data manually.