A holographic representation depicting the energy shield protecting the Death Star II
Force shields, also referred to as deflector shields, consisted of energy-based barriers capable of safeguarding starships, battle stations, ground installations, soldiers, and even entire armies from hostile attacks; some planets were even defended by enormous planetary shields. There were several kinds of deflector shields, such as ray shields, which were designed to deflect or disperse energy (although their effectiveness in completely neutralizing enemy fire varied), and particle shields, which served to mitigate the impact of high-speed projectiles and proton-based weaponry. Concussion shields, a third shield variant, were used to repel spaceborne debris and other solid matter. To achieve maximum protection, most starships employed a combination of ray and particle shields, while larger vessels sometimes required multiple projectors to fully cover the ship, with the shield's power decreasing as the distance from its projector increased.
Certain shields functioned as one-way barriers, permitting entry but preventing exit. Droidekas incorporated a built-in shield that could deflect standard blaster bolts, but it was ineffective against solid objects like thermal detonators or even individuals, provided they moved at a sufficiently slow pace.
Following the decline of the "dreadnought era," caused by the advent of advanced turbolasers with the capacity to penetrate ray shields, battleships only returned to use in spacelanes after Verpine engineers revolutionized deflector shield technology. However, they eventually fell out of favor again due to economic pressures and Republic limitations on capital ships exceeding the size of contemporary cruisers.
A VT-49 Decimator being protected from incoming fire by its deflector shield
The shield employed by the Confederacy of Independent Systems around its droid forces during the Battle of Christophsis is one example of how deflector-shield technology was used; it prevented the Grand Army of the Republic from launching an attack until the shield generator was disabled. A deflector shield was also present on the Millennium Falcon, which is a light freighter, and the DS-2 Death Star II Mobile Battle Station utilized a deflector shield powered by a deflector dish located on the forest moon of Endor.
During the Clone Wars era, the military forces of the Unknown Regions utilized electrostatic barriers that served a similar purpose to deflector shields, but with significantly less power. This prompted Thrawn to retrieve a deflector shield generator, which he referred to as a "Republic energy shield," from the Separatist droid factory on Mokivj and bring it back to his people after assisting Jedi Knight Anakin Skywalker on his mission to Batuu. Thrawn subsequently employed the "Republic energy shield" in the Battle over Primea to aid in the defeat of Nikardun General Yiv the Benevolent, effectively ending the Nikardun conquests. The Chiss heavy cruiser Steadfast, under the command of Admiral Ar'alani of the Chiss Expansionary Defense Fleet belonging to the Chiss Ascendancy, was equipped with deflector shields during the Imperial Era.
A Rebel soldier is seen utilizing a personal energy shield
Both Rebel Alliance and Imperial troops employed transportable shields that could be set up on virtually any surface. A compact generator projected the shield, creating a dome capable of protecting several individuals. The portable shield could effectively deflect any blaster fire, whether originating from outside or inside the shield. However, because its primary function was to shield ground troops, it permitted the passage of solid objects and individuals. A well-aimed detonator could destroy the generator and everything within the shield's confines. The shield's durability was also limited; it weakened under fire, with the shield's color shifting from blue to orange and ultimately to red before disappearing as the generator overheated.
Certain types of deflector shields were unusable under particular environmental conditions. For instance, the Xyston-class Star Destroyer was unable to activate its shields while stationed within the electrically charged atmosphere of the planet Exegol.
The Resistance MC85 Star Cruiser Raddus was outfitted with experimental deflector shielding. These shields were purportedly much stronger than standard shields and had the visible characteristic of a typically invisible bubble surrounding the ship.