Vehicular camera having a tubular lens unit and a tubular housing
A vehicular camera includes a lens unit, a circuit board, an imaging element, and a housing. The imaging element has first sensitivity in a first wavelength band having a wavelength shorter than a predetermined wavelength, and second sensitivity smaller than the first sensitivity in a second wavelength band having a wavelength longer than the predetermined wavelength. A first resin of a first tubular portion and a flange portion has first light transmittance in the first wavelength band and second light transmittance larger than the first light transmittance in the second wavelength band. A second resin of the housing has a third light transmittance smaller than the second light transmittance at least in the second wavelength band.
1 . A vehicular camera comprising:
a lens unit including a first tubular portion having a first tubular shape, at least one lens disposed inside the first tubular portion and on an optical axis, and a flange portion disposed outside the first tubular portion to extend outward with reference to the optical axis over an entire circumference centering on the optical axis;
a circuit board including a first surface and a second surface opposite to the first surface;
an imaging element disposed on the optical axis and on the first surface of the circuit board; and
a housing configured to accommodate at least the circuit board and the imaging element and including a second tubular portion having a second tubular shape along the optical axis, wherein
the second tubular portion of the housing includes
a first end, and
a second end that is opposite to the first end and is disposed at a position farther than the first end with reference to the lens unit in a direction of the optical axis,
the first tubular portion and the flange portion of the lens unit are integrally formed of a first resin,
the housing is formed of a second resin,
the first end of the second tubular portion of the housing is welded to the flange portion of the lens unit over the entire circumference centering on the optical axis,
the imaging element has
first sensitivity in a first wavelength band having a wavelength shorter than a predetermined wavelength, and
second sensitivity smaller than the first sensitivity in a second wavelength band having a wavelength longer than the predetermined wavelength,
the first resin of the first tubular portion and the flange portion has first light transmittance in the first wavelength band and second light transmittance larger than the first light transmittance in the second wavelength band, and
the second resin of the housing has a third light transmittance smaller than the second light transmittance at least in the second wavelength band.
2 . The vehicular camera according to claim 1 , wherein
the second resin of the housing has fourth light transmittance smaller than the second light transmittance also in the first wavelength band.
3 . The vehicular camera according to claim 1 , wherein
the first end of the second tubular portion of the housing is welded to the flange portion of the lens unit by laser light over the entire circumference centering on the optical axis.
4 . The vehicular camera according to claim 3 , wherein
the predetermined wavelength is one wavelength within a range of 1000 nm to 1200 nm.
5 . The vehicular camera according to claim 4 , wherein
the laser light has a wavelength longer than the one wavelength.
6 . The vehicular camera according to claim 1 , wherein
the flange portion of the lens unit includes
a first flange surface disposed along the first surface of the circuit board,
and
a second flange surface disposed along the first surface of the circuit board and located closer to the first surface of the circuit board than the first flange surface in the direction of the optical axis, and
the first end of the second tubular portion of the housing is welded to the second flange surface of the flange portion of the lens unit over the entire circumference centering on the optical axis.
7 . The vehicular camera according to claim 6 , wherein
the lens unit includes
a flange protruding portion protruding from the second flange surface of the flange portion toward the second end of the second tubular portion of the housing in the direction of the optical axis, and
at least three protrusions protruding from the flange protruding portion toward the first surface of the circuit board in the direction of the optical axis,
the at least three protrusions include a first protrusion, a second protrusion, and a third protrusion, and
the first tubular portion of the lens unit, the flange portion of the lens unit, the flange protruding portion of the flange portion, and the at least three protrusions of the flange protruding portion are integrally formed of the first resin.
8 . The vehicular camera according to claim 7 , wherein
the first protrusion of the flange protruding portion of the flange portion of the lens unit is bonded to the first surface of the circuit board with a first adhesive,
the second protrusion of the flange protruding portion of the flange portion of the lens unit is bonded to the first surface of the circuit board with a second adhesive, and
the third protrusion of the flange protruding portion of the flange portion of the lens unit is bonded to the first surface of the circuit board with a third adhesive.
9 . The vehicular camera according to claim 8 , wherein
the housing includes four side walls that are formed continuously with the second end of the housing and extend from the second end toward the second flange surface of the lens unit,
the four side walls are a first side wall, a second side wall, a third side wall, and a fourth side wall,
the first side wall of the housing is connected to the second side wall of the housing,
the second side wall of the housing is connected to the third side wall of the housing,
the third side wall of the housing is connected to the fourth side wall of the housing, and
the fourth side wall of the housing is connected to the first side wall of the housing.
10 . The vehicular camera according to claim 9 , further comprising:
an electrical connector including a first connector end and a second connector end opposite to the first connector end, and a connector connection portion disposed on the second surface of the circuit board, wherein
the electrical connector is disposed inside the second tubular portion of the housing,
the first connector end of the electrical connector is electrically connected to the connector connection portion on the second surface of the circuit board, and
the second connector end of the electrical connector is electrically connected to a cable of the vehicle when the vehicular camera is disposed in the vehicle.
11 . The vehicular camera according to claim 10 , wherein
the first tubular portion of the lens unit has a circular shape in a plan view of the first tubular portion,
the flange portion of the lens unit has a first rectangle in a plan view of the flange portion,
the flange protruding portion of the lens unit has a second rectangle having a smaller area than the first rectangle of the flange portion in a plan view of the flange protruding portion, and
the second tubular portion of the housing has a third rectangle having a larger area than the second rectangle of the flange protruding portion in a plan view of the second tubular portion.
12 . The vehicular camera according to claim 11 , further comprising:
a metal shield member having a third tubular shape, wherein
the shield member includes
a bottom surface, and
four side surfaces extending from the bottom surface toward the second flange surface of the flange portion of the lens unit in the direction of the optical axis, and
the four side surfaces of the shield member are a first side surface, a second side surface connected to the first side surface, a third side surface connected to the second side surface, and a fourth side surface connected to the third side surface.
13 . The vehicular camera according to claim 12 , further comprising:
a heat-conducting member disposed inside the third tubular portion of the shield member.