Optical unit

1. An optical unit comprising:

an optical sensor;

a nozzle that is positioned and configured to eject fluid onto an optical surface of the optical sensor, the nozzle including an internal fluid flow channel and a fluid outlet that receives the fluid from the internal fluid flow channel and that ejects the fluid directly onto the optical surface of the optical sensor, the nozzle being fitted to an outer periphery of the optical sensor; and

a holder that i) is a separate piece from the optical sensor and the nozzle and is movable relative to the optical sensor and the nozzle, including the fluid outlet of the nozzle, before being engaged with the optical sensor and the nozzle, ii) is slidably engaged over the optical sensor and the nozzle from a side of the optical sensor having the optical surface without coming between the optical sensor and the nozzle and iii) integrally fixes the optical sensor and the nozzle to each other.

2. The optical unit according to claim 1 , wherein

the internal fluid flow channel of the nozzle i) increases in width as the internal fluid flow channel extends from a base end side of the nozzle toward a distal end side of the nozzle and ii) decreases in thickness as the internal fluid flow channel extends from the base end side of the nozzle toward the distal end side of the nozzle.

3. The optical unit according to claim 1 , wherein

the nozzle has a shape that closely fits to the outer periphery of the optical sensor.

4. The optical unit according to claim 3 , wherein

the nozzle is placed on an upper portion of the optical sensor, and the fluid outlet has a shape that bends downward toward the optical surface.

5. The optical unit according to claim 3 , wherein

the optical sensor and the nozzle have concave portions on base end sides, respectively, and

the holder i) has convex portions corresponding in shape to the concave portions, respectively, ii) covers the optical sensor and the nozzle which are closely fitted to each other, and iii) integrally fixes the optical sensor and the nozzle to each other such that the convex portions are fitted in the corresponding concave portions.

6. The optical unit according to claim 5 , wherein

the holder has elastic tabs that snap-fit to the optical sensor and the nozzle.

7. The optical unit according to claim 1 , wherein

the holder has light shading parts formed by protrusions which surround an outer periphery of the optical surface.

8. The optical unit according to claim 3 , further comprising;

a bracket that i) has through-holes through which a wiring to the optical sensor and a pipe to the nozzle pass, respectively, ii) is configured to be mounted on a bracket mounting surface, and iii) is configured to support the optical sensor and the nozzle which are closely fitted to each other, on the bracket mounting surface.

9. A method of installing the optical unit of claim 1 , the method comprising the steps of:

mounting a bracket on a bracket mounting surface;

attaching a sealing member to the bracket;

placing the optical sensor of the optical unit on the sealing member and fixing the optical sensor to the bracket from a back side of the bracket;

passing the nozzle of the optical unit through the bracket and fixing the nozzle to the bracket from a front side of the bracket while the nozzle is closely fitted to the optical sensor; and

integrally fixing the optical sensor and the nozzle to each other by sliding the holder of the optical unit over the optical sensor and the nozzle from the side of the optical sensor having the optical surface.