US Patent 7738196 Optical unit

An optical unit is provided which includes gaps dR1 and dR2 in a radial direction that prevent an optical component from being affected by external stress during thermal expansion is formed between an outer circumferential surface of the optical component and an inner circumferential surface of a holder and gaps d0A1 and d0A2 that prevent the optical component adjacent to a pressing component from being affected by external stress during thermal expansion and are formed between predetermined surfaces on the pressing component and the optical component adjacent to the pressing component opposing each other in an optical axis direction.