Curtain airbag

1. 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.

2. The curtain airbag of claim 1 , wherein the first sub-chamber and the second sub-chamber are deployed prior to the main chamber.

3. The curtain airbag of claim 1 , wherein the first sub-chamber is formed in a longitudinal direction of the main chamber, and has a shape of a passage where the inflator is connected to a first end of the first sub-chamber and a second end thereof is closed, and a middle portion of the first sub-chamber is formed to communicate with an edge of the main chamber, and

the second sub-chamber is formed in the longitudinal direction of the main chamber, and has a shape of a passage where a first end of the second sub-chamber communicates with the edge of the main chamber and a second end thereof is closed.

4. The curtain airbag of claim 3 , wherein a peninsula region of a predetermined area which is not filled with gas is formed in at least one of between the second end of the first sub-chamber and the main chamber facing the second end, and between the second end of the second sub-chamber and the main chamber facing the second end,

a peninsula region around the first sub-chamber is formed such that edges thereof excluding one side are surrounded by an edge of the first sub-chamber and the edge of the main chamber, and

a peninsula region around the second sub-chamber is formed such that edges thereof excluding one side are surrounded by an edge of the second sub-chamber and the edge of the main chamber.

5. The curtain airbag of claim 1 , wherein a first end of a mounting tab is secured to the vehicle body, and

a second end of the mounting tab is secured between the main chamber and the second sub-chamber.

6. The curtain airbag of claim 5 , wherein the main chamber is folded in a roll shape, and

the second sub-chamber is folded over the main chamber to surround a lower end of the main chamber.

7. The curtain airbag of claim 6 , wherein a folding portion on an end of the second sub-chamber is inwardly folded towards the main chamber.

8. The curtain airbag of claim 6 , wherein a folding portion on an end of the second sub-chamber is outwardly folded towards the center of the vehicle.

9. The curtain airbag of claim 5 , wherein the main chamber is folded in a roll shape, and

the first sub-chamber is folded between the mounting tab and the vehicle body.

10. The curtain airbag of claim 9 , wherein a folding portion on an end of the first sub-chamber is inwardly folded towards the mounting tab.

11. The curtain airbag of claim 9 , wherein a folding portion on an end of the first sub-chamber is outwardly folded towards the vehicle body.