Rear-projection surfaces
In its private state, the glass is a projection screen
A switchable panel does not go dark when it is switched private. It scatters light — 94 to 95 per cent haze while transmitting most of what falls on it — which is the physical description of a diffusing screen. Put a projector on the far side and the partition that gives a meeting room its privacy is the surface it presents onto.
At the Berkley Group in Toronto that is exactly how the glass is used: privacy on demand in the meeting rooms, and the same panel as a whiteboard and a rear-projection surface. Its polarising behaviour lifts contrast enough to project in daylight with moderate ambient light in the room.
The haze figure is the specification
Rear projection needs a surface that scatters the image evenly and does not simply pass it through. That is what a switched PDLC or PNLC panel is:
| PDLC | PNLC (reverse) | |
|---|---|---|
| Haze, private state — the screen | 95% film | 94% film |
| Haze, clear state | 2.4% film | 3% film |
| Parallel light transmission, glass | 80% clear · 7% private | 80% clear · 7% private |
| State with no power | Private — a screen at rest | Clear — a window at rest |
| Time to become a screen | < 200 ms | < 5 ms |
| Time to clear again | < 10 ms | < 150 ms |
| Maximum panel | 70 × 165 in glass · 72 × 165 in film | 57 × 165 in |
A single panel of PDLC glass is 5 ft 10 in by 13 ft 9 in. That is a projection surface larger than most rooms have wall for, in a partition that was going to be there anyway — and there is nothing to unroll, nothing to lower and no frame around it.
What it is, and what it is not
It is a surface, not a display
There is no electronics in the glass and no image in the panel. The picture comes from a projector behind it, and the glass does what a rear-projection screen does — scatter it evenly towards the room.
The projector has to be behind it
Rear projection means the throw is on the far side of the glass, so the room behind the partition has to give up the depth the projector needs. Front projection onto a switched panel is a different proposition and a worse one.
Ambient light still matters
The Toronto installation projects in daylight with moderate ambient light in the room. That is a real working condition rather than a darkened one, but a bright south-facing wall is still a bright wall — the lighting design belongs in the conversation.
The panel is doing two jobs
Which is the argument. The privacy specification pays for the partition; the projection surface, the whiteboard and the absence of a screen in the ceiling come with it.
Which mode, for a room that presents
Both modes make the same screen. What differs is the state the room sits in when nothing is switched, and that is decided by how the room is used the rest of the week.
A presentation room — PDLC
Frosted with no power, so the screen is the resting state and the glass clears for the times the room is open to the floor. It is also the cheaper product and the larger panel.
A glazed meeting room — PNLC
Clear with no power, which is what an open-plan office wants for most of the working day. It becomes a screen in under 5 ms, and draws power only while the meeting is on.
Either way, one control
Wall switch, remote or the building system. A room that presents usually wants the partition on the same control as the projector, which is an integration decided with the AV contractor.
Common questions
Onto the private state, from behind. A switched panel is a diffusing surface at 94 to 95 per cent haze, which is what a rear-projection screen is. PriWatt has it in service at the Berkley Group in Toronto, where the partition is used as a whiteboard and a projection surface as well as for privacy.
The Toronto installation projects in daylight with moderate ambient light, helped by the polarising behaviour of the panel, which lifts contrast. It is not a darkened-room requirement, but ambient light and projector brightness still decide how good the image is and belong in the design.
A screen. There is no electronics in the glass and no image in the panel — the picture comes from a projector on the far side and the glass scatters it evenly towards the room.
It is used as one in Toronto. The switched panel is a flat, light, diffusing surface, and dry-erase marker behaves on glass the way it does on any glass board.
One panel of PDLC glass reaches 70 × 165 in — 5 ft 10 in by 13 ft 9 in. Larger surfaces are made from several panels, and where the joints fall is a design decision worth making before the projector is positioned.
Where this already exists
The Berkley Group, Toronto
Privacy on demand, a whiteboard and a rear-projection surface in the same partition — with an acoustic rating of Rw 35–36 dB.
Offices and boardrooms
The application page: what changes between a meeting room, a private office and an open floor.
Film and television
Studios and sets, where the panel is switched on camera rather than for privacy.
Built from the same six products
Doors
The one format where the glass moves, which makes the wiring the detail rather than the panel. Internal doors, entrances and glazed leaves in a partition run.
Read more
Shower enclosures
The room where the glass is the wall. Normal mode is frosted with no power, so a power cut leaves the enclosure private — which is the failure state a bathroom wants.
Read more
Skylights and overhead glazing
Overhead, the problem is usually the sun rather than the neighbours. DLC moves between a tinted transparent state and a deep dark one, which is glare and solar gain rather than privacy.
Read more
Curved glass
The curve is in the glass; the switchable layer follows it. Curved walls, columns and radiused partitions, made to the geometry rather than picked from a list of sizes.
Read more
Railings and balustrades
Two projects in service — a New York waterfront terrace and a North Palm Beach pool deck. Reverse mode holds the view with no power drawn, and frosts for the hour it is wanted.
Read more
Insulated units and facades
A switchable layer inside the insulating unit, on the exterior envelope. What it changes for solar gain, HVAC load and the elevation.
Read moreSend the opening, not the product code
Sizes, the shapes, whether the glass is already in the building and which state it should hold with no power. That is enough for a price and a lead time. Pompano Beach, Florida; (833) 333-8556.