Skip to main content
Get a quote

Technology

How PDLC and switchable glazing actually work — what is happening inside the panel, and what that means for a specification.

The mechanism

Two states, one layer of liquid crystal

A PDLC layer contains microscopic droplets of liquid crystal dispersed through a polymer matrix. Left alone, those crystals sit at random orientations. Light entering the layer hits thousands of differently-oriented droplets, scatters, and never emerges in a coherent direction. The result is a uniform translucent white — you can see that there is light on the other side, and nothing else.

Apply a voltage across the layer and the crystals align with the electric field. Light now passes through without being scattered, and the panel reads as clear glazing. Remove the voltage and they return to random orientation immediately.

Two delivery routes

The same physics, two very different products

The technology is identical. What differs is where the PDLC layer lives, and that decides which product suits a project.

  • Smart film — applied to installed glass

    The PDLC layer is manufactured as a self-adhesive film, 0.4–0.5 mm thick, bonded to the inner face of a pane that is already in place. Copper busbars at the edge carry the supply. This is the route for occupied buildings, leased space and refurbishment.

  • Smart glass — laminated at manufacture

    The PDLC layer is laminated between glass plies when the panel is made. The active layer is sealed inside, so the panel is handled, glazed and cleaned as ordinary architectural safety glass — and it carries the acoustic and retention benefits of lamination.

  • What that means for the choice

    New partitions, new doors and new glazing take laminated glass. Existing glazing, wet environments where the panel must be sealed, and situations where the change has to be reversible take film.

  • What does not change

    In both cases the unpowered state is opaque and the powered state is clear. Privacy is the default; transparency is what consumes power.

Control

How the switching is actually done

The glazing only asks for a switched low-voltage supply. Everything past that is a decision about how people will use the room.

  • Wall switch

    The default. Positioned where somebody entering the room would reach for a light switch.

  • Remote control

    Where the panel is not adjacent to a natural switch position, or where several zones are operated from one place.

  • Timer and schedule

    Retail frontage that switches out of trading hours; meeting rooms tied to a booking pattern.

  • Occupancy sensing

    Bathrooms and treatment rooms where privacy should not depend on somebody remembering.

  • Building or home automation

    Integration into the BMS or the home automation system, so the glazing behaves like the rest of the building.

  • Dimmer integration

    Where the requirement is graduated light control rather than two discrete states.

Reference

Technology at a glance

The values below are the published characteristics of the switchable range. Confirm tested values for a specific product and assembly before specifying.

The power consumption, UV and infrared figures are TouchActiv product performance claims. Request written confirmation of tested values before use in a specification.

TechnologyPolymer-Dispersed Liquid Crystal (PDLC)
Unpowered stateOpaque — light scattered, view obscured
Powered stateTransparent — crystals aligned, light transmitted
SwitchingEffectively instantaneous; no moving parts
Film thickness0.4 – 0.5 mm
Maximum film sheet1.5 m × 2.7 m
Glass thickness options5, 6, 8 and 10 mm
Glass typesFloat, tempered, ultra-white, tinted
Power consumptionLow — comparable to a clock radio (source-stated)
UV / IR behaviourBlocks 99%+ UV and 80%+ infrared (source-stated)
Secondary functionRear-projection screen in the opaque state

FAQ

Questions we are asked

How the technology behaves once it is installed — the questions that come up on nearly every specification.

What is the difference between smart glass and smart film?
The technology is the same. In smart glass the PDLC layer is laminated inside a glass panel at manufacture; smart film is applied to glass that is already installed. New build and new partitions usually take glass; occupied and leased space usually takes film.
What happens in a power cut?
The film reverts to its unpowered state, which is opaque. Privacy is the default and transparency is the powered condition.
Does photochromic film need power?
No. It reacts to incident light, so there is nothing to wire, switch or schedule.
Can smart window film be fitted to glass that is already installed?
Yes. That is its main advantage over laminated switchable glass. The film is bonded to the inner face of the existing pane, so occupied space can be upgraded without replacing the glazing.
How is electrochromic film different from photochromic film?
Electrochromic film is switched — you or the building system decide the tint state. Photochromic film reacts to incident light on its own. Where the requirement is control, specify electrochromic; where it is automatic response, photochromic.
What maintenance does it need?
There is no fuel input and there are no moving components, so maintenance demand is minimal and largely aligns with normal facade cleaning and inspection.

Next step

Have a technical question we have not answered?

Ask it directly. Technical questions get a technical answer, not a sales call.

Request a quote Talk to our team