The Vedens perfected them. Recently invented fabrials from Jah Keved, they represent an attempt to recreate the powers of Shardplate using fabrial science. However, they use a completely different design principle from regular Shardplate: they can only take the shape of a shield and don't lend any of Shardplate's other enhancements.
The Half-Shard shields have distinctive, diamond-like shapes. They are made of metal imbedded with a gemstone hidden at the back, which can be infused with Stormlight, thereby enhancing its durability.