Curtain airbag

A curtain airbag, comprising:

• a main chamber of an airbag cushion secured to an upper end inside a vehicle body to be deployed toward a lower end thereof;
• a first sub-chamber of the airbag cushion deployed above a pillar trim while pushing the vehicle body to move the main chamber towards a center of a vehicle;
• and
• a second sub-chamber of the airbag cushion deployed between an end of the pillar trim and the main chamber, thus pushing the main chamber to prevent the main chamber from being caught by the end of the pillar trim;
• wherein:
• a diffuser is secured to an interior of the airbag cushion;
• an inflator is connected to an inlet of the diffuser to introduce gas therein, and
• an outlet of the diffuser is formed in each of the main chamber, the first sub-chamber, and the second sub-chamber to diffuse the gas introduced into the diffuser into each chamber;
• wherein the inlet of the diffuser is connected to a first sub-outlet formed in the first sub-chamber and a first main-outlet formed in the main chamber to diffuse gas thereto, and the first main-outlet is connected to a second sub-outlet formed in the second sub-chamber and a second main-outlet formed in the main chamber to diffuse the gas thereto.