Primary Ad Unit: Full-Screen vs. Partial-Screen DOOH Explained

A primary ad unit is the main space on a screen where an ad appears. In Digital Out-of-Home (DOOH), it falls into one of two categories: full-screen, where the ad occupies the entire display, or partial-screen, where it shares the screen with wayfinding, menu items, or another advertiser. That classification isn’t a formatting detail: it determines the CPM a screen can command, whether it’s sold via programmatic guaranteed or open exchange, and the creative spec an advertiser must deliver.

Note: a primary ad unit (full-screen vs. partial-screen) is a different attribute from primary ad unit orientation, which describes landscape vs. portrait. The two are set independently: a screen can be a full-screen unit in portrait, or a partial-screen unit in landscape.

Full-Screen vs. Partial-Screen Primary Ad Units

Full-screen primary ad units give the advertisement the entire display, capturing the viewer’s full attention. This is the default configuration for most classic Digital Out-of-Home (DOOH) formats. Because there’s no competing content, the creative occupies the viewer’s full field of view for the entire play. That is why these units command the highest CPMs in a media owner’s inventory.

Partial-screen primary ad units share the display with non-ad content or with another advertiser. Common examples include:

• A mall directory board where the ad occupies a fixed panel alongside a wayfinding map.
• A quick-service restaurant menu board with a rotating ad zone built into the layout.
• A split-screen retail display running two advertisers’ creatives side by side.
• A transit information screen where the ad shares real estate with arrival times.

Partial-screen units may see lower CPMs than full-screen placements on the same network, because the viewer’s attention is divided.

For the technical side of screen selection, resolution, aspect ratio, and format-by-venue breakdowns, see Perion’s guide to choosing winning DOOH screen formats.

Why Full-Screen vs. Partial-Screen Primary Ad Units Affect Pricing

Media owners don’t price inventory by venue alone; they price it by how much of the screen, and how much of the viewer’s attention, an ad gets.

• Full-screen units are the premium tier of most DOOH networks. Because they deliver undivided visual impact, they’re the units most likely to be offered through programmatic guaranteed deals or held back as premium ad inventory for advertisers who want reserved, predictable delivery at a fixed price.
• Partial-screen units are commonly sold through the open exchange or private marketplace deals, since they represent secondary or fill inventory rather than a network’s flagship placements.

This is also why the classification matters as much to media owners as to advertisers. Through Demand Manager, publishers can classify and route full-screen and partial-screen inventory differently across demand sources.

Primary Ad Unit Creative Implications for Advertisers

The primary ad unit classification isn’t only a pricing signal; it’s also a creative brief.

Full-screen creative can use the entire canvas: full video or static imagery, no competing visual elements. Depending on venue and dwell time, there must be slightly more room for copy.

Partial-screen creative works inside a smaller, shared frame, often with a fixed safe zone dictated by the surrounding layout (a menu board grid, a directory panel). That constraint pushes toward tighter copy and simpler visuals.

Primary Ad Unit in Practice

Perion’s Bakers Delight campaign is a useful illustration of how unit selection shapes execution. To drive footfall for the brand’s inaugural “National Hot Cross Bun Day,” Perion activated screens within a 5km radius of each bakery across five Australian states, concentrating spend on high-traffic retail environments such as malls and convenience stores – the venue types where partial-screen and shared-attention placements are most common. 

Creative was dynamically generated in real time to name the nearest bakery location, a direct response to the tighter, more localized attention these environments demand. A placement’s classification should shape the creative brief before a single design is opened, not after.