A side airbag is disposed at a side of a seat of a vehicle and inflated with gas supplied from a gas generator. The scanning low coherence interference signal includes two or more overlapping low coherence interference signals, each of which results from a respective interface. A second capacitor has a first node coupled to a second node of the inductor and has a second node coupled to ground. 0 mass %, containing substantially none of thickening stabilizers. This optical reflection element reduces unnecessary vibration, and projects clear images.